TABLE of CONTENTS

VI. Proposed Vehicle-To-Pole Test Procedures, Dummies and Injury Criteria

This NPRM proposes subjecting all vehicles [17] with a GVWR of 4,536 kg (10,000 lb) or less to a dynamic vehicle-to-pole test that is similar to the one used to test some vehicles under FMVSS No. 201, except that we are proposing to change the angle of impact from 90 to 75 degrees (which would result in bags having to cover a larger area of the window exposed to occupant contact), and the test speed from 29 to 32 km/h (from 18 to 20 mph) (which would increase the severity of the test). [18] The purpose of requiring vehicles to satisfy this test is to ensure protection for occupants in a wider range of real world impacts than would be the case if we used the FMVSS No. 201 pole test.

A test dummy capable of measuring head injury potential would be used to represent a 50th percentile male. NHTSA proposes to adopt the ES-2re dummy for use in the pole test and in the barrier test, since, as discussed in a later section, we have tentatively determined that the dummy is technically superior to the SID-H3 test dummy used in FMVSS No. 201 and to the SID used in FMVSS No. 214. Alternatively, we request comments on using the SID-H3 dummy, since it can measure the risk of head injury. In addition, the NPRM proposes to use the modified SID-IIs dummy representing a 5th percentile female in both the pole and MDB tests. These dummies together better represent the at-risk population than those in the current standard.

The agency is proposing to adopt a vehicle-to-pole test similar to that specified in FMVSS No. 201, with modifications relating to the angle and speed at which the test vehicle is propelled into the pole and to the test dummies used in the test and the positioning of those dummies. Based on the agency’s experience in the FMVSS No. 201 compliance test program and in research done in support of today’s NPRM, NHTSA tentatively concludes that the vehicle-to-pole test proposed today would better address the harm caused by narrow object impacts in the real world, and lead manufacturers to equip their vehicles with upper interior, dynamically deploying head protection systems. [19]

The pole would have the same specifications as the pole used in the vehicle-to-pole test specified in FMVSS No. 201. It would be a vertical metal structure beginning not more than 102 mm (4 inches) above the lowest point of the tires on the striking side of the test vehicle when the vehicle is loaded as specified in the standard and extending above the highest point of the roof of the test vehicle. The pole would be 254 mm (10 inches) ± 6 mm in diameter and set off from any mounting surface such as a barrier or other structure, so that a test vehicle would not contact such a mount or support at any time within 100 milliseconds of initiation of vehicle-to-pole impact.

As we noted in the rulemaking adding the vehicle-to-pole test to FMVSS No. 201 (63 FR 41451, 41457; August 4, 1998), the 254 mm (10 inch) pole diameter differs from the pole diameter specified by ISO in its final recommendation. ISO specifies a pole diameter of 350 mm (14 inches). The diameter of the rigid pole specified in FMVSS No. 201 was set at 254 mm in 1998 based on data from the Federal Highway Administration (FHWA) that the pole diameter at the window sill level for most poles involved in single vehicle side crashes was approximately 254 mm (10 inches). FHWA has informed NHTSA that there are 80 million timber utility poles in the roadside environment and that the most common size pole would have a diameter of 254 mm (10 inches) at the mid-height of passenger car doors. (See July 11, 2003 memorandum, a copy of which is in the docket.) Therefore, the 254 mm (10 inch) diameter rigid pole is representative of poles struck in side crashes in the U.S.

In a vehicle-to-pole test, the center line of the rigid pole is aligned with an impact reference line drawn on the struck side of the vehicle. In the procedures for the proposed oblique pole test, the impact reference line is in a vertical plane that passes through the center of gravity (CG) of the dummy’s head in a direction that is 75 degrees from the vehicle’s longitudinal center line. When conducting a test with the 50th percentile male dummy, the dummy and the vehicle seat would be positioned as in FMVSS No. 214 (mid-track fore-and-aft). When conducting a test with the 5th percentile female dummy, the vehicle seat would be positioned full-forward. In today's proposed pole test, the initial pole-to-vehicle contact must occur within an area bounded by two vertical planes located 38 mm (1.5 inches) forward and aft of the impact reference line. [20]

The agency’s tests conducted in support of this NPRM demonstrate the repeatability of the proposed oblique pole test. NHTSA conducted three repeatability tests using the 1999 Nissan Maxima. The test results show that the location of first contact between the pole and vehicle exterior were in the range of 2 mm (0.08 in) and 15 mm (0.59 in) rearward of the impact reference line. In all three tests, the head of the ES-2 dummy contacted the pole. Later, NHTSA conducted two additional oblique pole tests using 1999 Volvo S-80 cars. Test results show that the contact lines were 5 mm (0.2 in) and 32 mm (1.26 in) rearward of the impact reference line. One test was conducted with a SID-H3 dummy and another with an ES-2 dummy. (While the head of both dummies contacted the pole, the SID-H3 head rotated off the air curtain directly into the pole, resulting in a very high HIC score.) In conclusion, in all five tests, the contact lines were within the 38 mm (1.5 inch) tolerance limit specified in the FMVSS No. 201 procedure and in this proposal, and the dummy’s head contacted the pole directly in tests without an inflatable head protection system (HPS) or indirectly (including head rotating into the pole) in tests with an HPS.

The aforementioned tests were conducted with the vehicle seat positioned as specified in FMVSS No. 201. [21] Two oblique pole tests with the seat positioned mid-track, as specified in FMVSS No. 214, were completed with each of the 1999 Volvo S-80 and 2000 Saab vehicles. The impact lines for the four tests were all less than 19 mm (0.75 inches), well within the tolerance of 38 mm (1.5 inches) of the impact reference line.

The proposed test speed is 32 km/h (20 mph). Crashes with delta-V 32 km/h (20 mph) or higher result in approximately half of the seriously injured occupants in narrow object near-side crashes. The derivation of the median delta-V (32 km/h or 20 mph) was based on all belted occupants with serious injuries in 1990-2001 NASS near-side crashes with narrow objects regardless of impact angles. Based on the lateral delta-V, a test speed of 29 km/h (18 mph) for the 90-degree pole test would be slightly over 30 km/h (19 mph) in a 75-degree pole test. Based on these data, NHTSA tentatively concludes that a 32 km/h (20 mph) test would be more appropriate than a 29 km/h (18 mph) test speed, because it better corresponds to the speed of real world crashes that result in serious injury.

Comments are requested on the alternative of a 29 km/h (18 mph) test speed. The 29 km/h (18 mph) test speed is used in the perpendicular pole test of FMVSS No. 201.

This NPRM proposes that the angle at which a vehicle is propelled into the rigid pole would be 75-degrees rather than the 90-degree angle used in FMVSS No. 201. (This test using the 75-degree impact angle is sometimes referred to in this document as the "oblique pole test.")

In the oblique pole test, when testing the driver side of the vehicle, an impact reference line would be drawn on the vehicle’s exterior where it intersects with a vertical plane passing through the head CG of the seated driver dummy at an angle of 75 degrees from the vehicle’s longitudinal centerline measured counterclockwise from the vehicle’s positive X axis as defined in S10.14 of the proposed standard. When testing the front passenger side, the impact reference line would be drawn where it intersects with a vertical plane passing through the head CG of the passenger dummy seated in the front outboard designated seating position at an angle of 285 degrees from the vehicle’s longitudinal centerline measured counterclockwise from the vehicle’s positive X axis as defined in S10.14 of the proposed standard. The vehicle is aligned so that, when the pole contacts the vehicle, the vertical center line of the pole surface as projected on the pole's surface, in the direction of the vehicle motion, is within a surface area on the vehicle exterior bounded by two vertical planes in the direction of the vehicle motion and 38 mm (1.5 inches) forward and aft of the impact reference line. The test vehicle would be propelled sideways into the pole. Its line of forward motion would form an angle of 75 degrees (or 285 degrees) (±3 degrees) in the left (or right) side impact measured from the vehicle’s positive X-axis in the counterclockwise direction.

The agency tentatively concludes that the proposed oblique pole test would enhance safety because it is more representative of real-world side impact pole crashes than a 90-degree test. Frontal oblique crashes, i.e., at a principal direction of force (PDOF) of 74 to 84 degrees clockwise or counter clockwise from 12 o’clock, account for the highest percentage of seriously injured (MAIS 3+) near-side occupants in narrow object crashes. However, the crash data also show that the PDOF distribution encompasses a wide range of approach angles, where the mean cumulative distribution is a 60-degree impact angle. (As discussed later in this section, a steeper angle than 75-degrees is not considered appropriate because of the need for repeatability of the test procedure.)

The oblique pole test also meets the need for safety because, unlike a 90-degree pole test, it exposes the dummy’s head and thorax to both lateral and longitudinal crash forces that are typically experienced in rear world side impacts. Weighted 1990-2001 NASS/CDS side impact data show that in narrow object crashes, serious head and chest injuries are dominant for both small and large stature occupants. Therefore, in developing the oblique pole test procedure, the agency sought to establish a performance test that would both emulate the real world crash conditions while providing head and chest injury reduction benefits in the identified target population.

NHTSA believes that an oblique impact angle would also serve the safety need because the test is likely to result in wider inflatable head protection systems and thus protect occupants over a wider range of impacts with narrow objects. A head air bag just wide enough to meet a perpendicular pole test might not provide benefits during an oblique crash, as the head of an occupant could move laterally and forward at an angle rather than moving strictly laterally into the head air bag. For example, in a 75-degree test of a Nissan Maxima with the ES-2 dummy, the combination head/thorax side impact air bag was too small to prevent the occupant head from rotating into the pole. The HIC score was 5,254. In a 90-degree test, the same MY Maxima produced successful results, with a HIC score of 130. This contrast in results between the 75- and 90-degree tests shows up repeatedly in tests of other vehicles as well. A 1999 Volvo S-80 with an air curtain and chest air bag tested obliquely with the SID-H3 resulted in a HIC of 2,223, while a HIC of 237 was achieved in a 90-degree test. [22] These data are presented in more detail later in this document and in the Preliminary Economic Assessment accompanying this NPRM.

An air bag might also fail to inflate in an oblique crash if the side air bag system were closely tuned to sensing and responding in a 90-degree test using a 50th percentile male dummy. As discussed later in this preamble, data from crash tests conducted in support of this rulemaking show that side air bags in a Ford Explorer and a Toyota Camry that were certified as meeting the requirements of the 90-degree pole test of FMVSS No. 201 did not inflate at all in an oblique (75 degree) test using a 5th percentile female dummy. The HIC results for the 5th percentile female (SID-IIsFRG) dummy placed in the driver’s seats of these vehicles were in the thousands (13,125 and 8,706, respectively).

Comments are requested on NHTSA’s conclusions that combination and head protection air bags would generally need to be wider if the agency adopted a 75-degree vehicle-to-pole test instead of a 90-degree one, particularly if the ES-2re and SID-IIsFRG dummies were both used in testing side air bags. NHTSA believes that present seat-mounted head/thorax air bags would need to be redesigned to extend the air pocket substantially further forward toward the A-pillar to provide coverage in a 75-degree oblique test. The air bags would likely need a more robust inflation system and a larger size to reach the part of the vehicle that would be struck by the dummy’s head in a 75-degree pole test. [23]

In contrast, side curtains might not need to be substantially widened to meet an oblique pole test. The agency believes that most current side air curtains are tethered to the A- and C-pillars of vehicles and generally would need less redesign than seat-mounted bags to meet an oblique pole test.   Air curtains might thus be the countermeasure chosen by many manufacturers to meet the vehicle-to-pole test requirements proposed today.

In addition, after evaluating research conducted on a number of HPS, the agency has determined that air curtain systems could be effective in preventing or reducing complete and partial occupant ejection through side windows. "Rollover Ejection Mitigation Using Inflatable Tubular Structures," Simula, et al., 1998; "Status of NHTSA’s Ejection Mitigation Research Program," Willke, et al., ESV 2003. This is important because the fatality rate for an ejected vehicle occupant is three times as great as that for an occupant who remains inside of the vehicle.

The best way to reduce complete ejection is for occupants to wear their safety belts. However, of the 5,400 ejected fatalities through front side windows, 2,200 are from partial ejections. Fatal injuries from partial ejection can occur even to belted occupants, [24] when their head protrudes outside the window and strikes the ground in a rollover or even the striking object (e.g., pole or a taller vehicle hood) in a side impact.

While the cumulative distribution of the angle of approach of near-side narrow object crashes has a mean of 60 degrees, based on its research, the agency has concluded that the 75-degree impact is repeatable to simulate in a laboratory test while a 60-degree impact is not. The more oblique the angle is, as measured from the lateral direction (e.g., 30 degrees for the 60-degree impact versus 15 degrees for the 75-degree impact from the longitudinal direction), the more difficult it is to control dummy head and/or body kinematics (specifically, direction of the dummy head motion). For more oblique angles (as measured from the lateral direction), at the initial pole-to-vehicle contact, the lateral distance from the centerline of the pole to the head center of gravity is larger, and more of the vehicle structure, specifically the seat, is involved in that crush space. Different seat designs and structural attachments to the vehicle body could produce inconsistent dummy readings because of the varying dummy head/body kinematics and the head not consistently contacting the approaching 254 mm (10-inch) pole.

Comments are requested on the appropriateness and practicability of using the 75-degree angle of approach as well as the 90-degree impact angle now used in the optional pole test of FMVSS No. 201.

50th percentile male dummy. In the oblique pole test, an impact reference line would be placed on the exterior of the vehicle at the intersection of the vehicle exterior and a 75-degrees (or 285-degrees, for front passenger side) vertical plane passing through the center of gravity of the head of the driver (or passenger) dummy seated in the front outboard designated seating position. The 50th percentile male test dummy and the front vehicle seat would be positioned along the seat track as the dummy and front seat are positioned in the MDB test of FMVSS No. 214. (As noted below, the agency is also considering positioning the dummy and vehicle seat along the seat track using the FMVSS No. 201 seating procedure.)  Under the FMVSS No. 214 procedure, the vehicle seat is positioned mid-track fore-and-aft. (This provision would only apply to the front seat, as the pole test would not apply to the rear seat.)

NHTSA test data indicate that the FMVSS No. 201 and FMVSS No. 214 seating procedures can result in different HIC measurements when using the SID-H3 dummy (see Table 4, infra). When a 1999 Volvo S-80 was tested in an oblique pole test with a SID-H3 50th percentile dummy, the HIC was 2,213 when the FMVSS No. 201 seating position was used, as opposed to 395 when the FMVSS No. 214 seating position was used. The side air bag system in the Volvo was an air curtain and thorax bag. Similarly, when a 2000 Saab was tested obliquely with the SID-H3 50th percentile male dummy, the HIC was 5,155 using the FMVSS No. 201 seating procedure, as opposed to 182 using the FMVSS No. 214 seating position. The Saab’s side air bag system was a combination bag. Compared to the FMVSS No. 201 seating position, the FMVSS No. 214 seating position can place the dummy rearward and closer to the B-pillar. Since the production side air bag system was wide enough to cover the dummy head trajectory in this seating position, the HIC values were significantly lower in these oblique tests.

However, when the ES-2re dummy was used, differences in HIC were not so pronounced. The HIC score for the 1999 Volvo S-80 was 465 when using the FMVSS No. 201 procedure, as opposed to 329 when the dummy was seated according to FMVSS No. 214 seating specifications. The HIC for the Saab was 243 using FMVSS No. 201 seating procedure, and 171 using the FMVSS No. 214 procedure. The difference between the results of the two dummies is due to small differences in the dummy head/neck/shoulder kinematics and the tuning of current head protection air bag systems to provide limited coverage in lateral impacts. In both the Volvo S-80 and the Saab oblique pole tests with the ES-2, the deploying air bag lifted the articulated arm upward and inboard and the head bent laterally and contacted the bag along a main air chamber. In the case of the two oblique pole tests with the SID-H3, the dummy had rotated slightly forward and contacted the bag systems at a more forward section, resulting in contact with the intruding pole in the case of the Saab. It is also noted that air curtains are currently designed for the FMVSS No. 201 pole test, in which the SID-H3 dummy is used. In some cases, the air curtain might not be large enough to provide coverage to the SID-H3 dummy in an oblique crash.

Rib deflection measurements differed slightly when the different seating positions prescribed in FMVSS No. 201 and No. 214 were used in the Volvo. Rib deflections were 40.70 mm (1.6 in) and 48.6 mm (1.91 in) when the FMVSS Nos. 201 and 214 procedures, respectively, were used. (The 48.6 mm rib deflection value obtained when the FMVSS No. 214 procedure was used would not meet this NPRM’s proposed criterion of 44 mm.)  Chest deflections did not differ significantly in the Saab in dummies positioned according to the FMVSS No. 201 and FMVSS No. 214 procedures (49.9 mm (1.96 in) versus 49.4 mm (1.94 in)).

We have tentatively decided to use the FMVSS No. 214 seating procedure for the vehicle-to-pole test proposed today. The FMVSS No. 201 procedure is appropriate for that standard’s pole test in order to place the SID-H3’s head in the window opening, thus ensuring contact with a deploying head air bag and eliminating head interaction with the B-pillar. [25] In the context of FMVSS No. 201, isolating the head air bag in this manner evaluates the effectiveness of the head air bag, which accords with the goal of that standard. An air bag in FMVSS No. 201, though optional, would provide more protection than any interior component protected by padding or other energy-absorbing material. However, an air bag designed to meet the current proposal would offer more protection over a larger area and therefore, is expected to be more effective and yield more safety benefits than the air bags offered under the optional pole test requirement in FMVSS No. 201.

Using the FMVSS No. 214 seating procedure has certain advantages when used in the oblique pole test. First, many mid-size occupants might use the mid-track position more typically than the one closer to the steering wheel specified under FMVSS No. 201. Second, using the FMVSS No. 214 procedure positions the 50th percentile male dummy further back towards the B-pillar than the FMVSS No. 201 seating procedure. By having the 50th percentile male dummy sitting at that position and the 5th percentile female dummy sitting full forward, the agency can ensure a test of as wide an area as possible. The agency believes that rearward positioning of the 50th percentile male dummy and the much further forward seat position for the 5th percentile female dummy (and the lower position of the 5th percentile female dummy’s head) would result in head air bag designs that provide head protection through much or all of the window opening area. For these reasons, the agency is proposing to use the FMVSS No. 214 seating procedure for the 50th percentile male dummy in the oblique pole test. The agency seeks comments on which seating position (FMVSS No. 201 versus No. 214) is appropriate.

5th percentile female dummy. The procedures for determining the impact reference line for the test using the 5th percentile female dummy would be similar to that discussed above for determining the line when using the male dummy.

Dummy positioning would differ, in that the female dummy would be positioned in the vehicle seating position in the manner described in S16.3.2 to S16.3.5 of FMVSS No. 208. That is, the dummy would be seated with the seat track in the full forward position. The agency tentatively concludes that a properly designed inflatable system should and can provide protection in that location.

Crash data indicate that the 50th percentile male dummy is generally representative of the height and weight of occupants injured in collisions with passenger vehicles and with narrow objects. [26] The median height and weight of the injured occupants in crashes with passenger cars (on the struck side of a vehicle) are 1,701 mm (67 inches) and 72.1 kg (159 lb), and 1,701 mm (67 inches) and 71.2 kg (159.5 lb) in collisions with LTVs. The median height and weight of the injured occupants in crashes with narrow objects are 1,715 mm (67.5 inches) and 72.3 kg (159.5 lb). Nearly 59 percent of all MAIS 3+ injuries occurred to occupants in the medium height stature category.

As noted earlier, there are now improved test dummies that represent the 50th percentile male better than the SID. In 2000, NHTSA granted in part a petition for rulemaking from the AIAM, the Insurance Institute for Highway Safety, and the organization then called the American Automobile Manufacturers Association. The petitioners asked NHTSA to examine replacing the SID with an enhanced side impact dummy (see section IV(i), above). The petitioners suggested that NHTSA replace the SID with a test dummy (EuroSID-1) used in a European side impact standard (EU/96/27/EC). Although the agency concluded that EuroSID-1 had problems in measuring chest deflections accurately because of "flat topping" of responses, which rendered it unsuitable for use in FMVSS No. 214, we granted this part of the petition because we anticipated that the problems could be cured and that a dummy technically superior to the SID could be incorporated into FMVSS No. 214. (“Flat topping” refers to sustained peaks (plateaus of flat-tops) in plots of the dummy’s rib displacements over time. NHTSA observed sustained peaks as long as 15 milliseconds in rib displacement curves in tests using the EuroSID-1. “Comparative Performance Testing of Passenger Cars Relative to FMVSS 214 and the EU 96/EC/27 Side Impact Regulations: Phase 1”, Samaha et al, Paper No. 98-S8-O-08, 16 th International Technical Conference on the Enhanced Safety of Vehicles, Windsor, Canada 1998. Rib deflection flat tops were deemed to be of concern, especially at low levels of deflection, as they can be an indication that the rib deflection mechanism is binding and thus the thorax is not responding correctly to the load from the intruding side structure. Accordingly, the resulting peak deflections would be of questionable usefulness as injury indicators.) Users of the dummy in Europe subsequently determined that the EuroSID-1 design allowed a spurious load path through the back plate in the dummy and thus transferred chest loads through the back plate, giving erroneous chest deflection readings.

The problems of the EuroSID-1 appear to have been eliminated with the evolution of the dummy into the ES-2 side impact dummy and the subsequent changes made with respect to the ES-2’s rib design. The ES-2re dummy is more biofidelic than SID and offers more injury measurement capabilities than the present side impact dummy. Thus, using this improved dummy would enhance the protection afforded by vehicles to the affected population, especially those represented by a 50th percentile male dummy. [27]

The ES-2 dummy evolved from the EuroSID and EuroSID-1 dummies. EuroSID existed when NHTSA adopted the dynamic moving deformable barrier test into FMVSS No. 214 in 1990. However, when the agency examined the dummy, NHTSA determined that EuroSID suffered from a number of technical problems involving "flat topping," [28] biofidelity, reproducibility of results, and durability. Because of these limitations, in 1988 NHTSA decided against adopting EuroSID and instead adopted SID as the test device used in the dynamic FMVSS No. 214 test.

The EuroSID was developed in the 1980s, and a revised version known as EuroSID-1 is currently specified as the test dummy to be used in ECE Regulation No. 95 and European Union (EU) Directive 96/27/EC (hereinafter EU 96/27/EC) for side impact testing. As noted above, in 1996, Congress asked NHTSA to consider whether the dynamic side impact provisions of the European side impact regulation, including those specifying use of the EuroSID-1 dummy, were at least functionally equivalent to those in FMVSS No. 214. NHTSA developed and provided Congress with its side impact harmonization plan [29] that set forth NHTSA’s planned research to evaluate the functional equivalence of the two standards and later, by update, the results of that research. NHTSA performed a series of crash tests of FMVSS No. 214 compliant vehicles using the EU test procedures and the EuroSID-1 dummy.

A main finding was that in all tests conducted, data for dummy rib deflections indicated flat topping. With flat topping, the resulting rib deflections and the V*C computations, [30] which are based on the rib deflection, are suspect. Due to this anomaly and others in the measurements obtained with the European dummy, the agency determined that it was not possible to generate the data necessary to determine whether the European standard and its requirements are at least functionally equivalent to the provisions in FMVSS No. 214. The data did show, however, that the EuroSID-1 dummy was not suitable for use in FMVSS No. 214.

Since that time, the EuroSID line of dummies has made steady progress toward resolving these issues, with the ES-2re being the latest version. The ES-2 was designed to overcome the concerns raised by NHTSA and users of the dummy worldwide. [31]  Beyond flat topping, concerns had been raised about the projecting back plate of the dummy grabbing into the seat back, upper femur contact with the pubic load cell hardware, binding in the shoulder assembly resulting in limited shoulder rotation, and spikes in the pubic symphysis load measurements associated with knee-to-knee contact. To address these concerns, the dummy manufacturer installed hardware upgrades in the ES-2, including an improved rib guide system in the thorax, a curved and narrower back plate, a new attachment in the pelvis to increase the range of upper leg abduction and inclusion of rubber buffers, a high mass flesh system in the legs, and beveled edges in the shoulder assembly.

The ES-2’s back plate continued to grab the seat back in some of NHTSA’s tests, despite the dummy manufacturer’s initial efforts to address the problem by reducing the size and shape of the back plate. The dummy manufacturer was able to solve the flat topping problem by redesigning the rib module. The back plate problem was solved by adding rib extensions, i.e., replacement ribs that extend from the lateral portion of the non-struck thorax, around the sternum and struck-side, and end at the posterior aspect of the spine. The extended ribs provide a continuous loading surface that nearly encircles the thorax and enclose the posterior gap of the ES-2 ribcage. According to NHTSA’s test data, these "rib extensions" reduce to a great extent the back plate grabbing force that had the effect of lowering rib deflection responses in tests. The rib extensions also do not appear to affect the dummy’s rib deflection responses in tests in which high back plate loads did not occur.

The ES-2 dummy has not yet supplanted the EuroSID-1 dummy in Europe or elsewhere for use in regulations as of this time. However, based on a proposal from the Netherlands, the UN/ECE’s Working Party on Passive Safety (GRSP) has recommended to the WP.29 that ECE Regulation No. 95 be amended to use the ES-2 dummy in place of the EuroSID-1. [32] The GRSP’s proposal takes into account the modifications that NHTSA has done to ES-2 to fix the back plate problem, as well as other minor outstanding technical problems raised by other participants. If this is adopted, the European Union is expected to also amend its Directive 96/27/EC to use the ES-2 dummy.

Using the ES-2re in FMVSS No. 214 would also accord with the practices of the non-governmental European New Car Assessment Program (EuroNCAP) on side impact.   EuroNCAP began using the ES-2 dummy with the injury criteria specified in EU 96/27/EC in February 2003.

In light of the above modifications and the anticipated benefits of this dummy, NHTSA believes that the ES-2re merits consideration for incorporation into Part 572 and for use in FMVSS No. 214 testing. Based upon the ES-2re’s superior biofidelity and added measurement capabilities for injury assessment of many body regions and associated instrumentation, we have tentatively decided that the ES-2re is the preferred option for the 50th percentile male dummy. As part of a separate rulemaking action, NHTSA is currently in the process of "Federalizing" the ES-2re dummy. A technical report and other materials describing the ES-2re in detail have been placed in the Docket for today’s NPRM. A proposal to incorporate the specifications for the ES-2re in Part 572 will be published shortly in the FEDERAL REGISTER.

Biofidelity, Repeatability and Reproducibility. Biofidelity is a measure of how well a test device duplicates the responses of a human being in an impact. The Occupant Safety Research Partnership and Transport Canada conducted biomechanical testing on the ES-2 dummy. Byrnes, et al., "ES-2 Dummy Biomechanical Responses," 2002, Stapp Car Crash Journal, Vol. 46, p. 353. Biomechanical response data were obtained by completing a series of drop, pendulum, and sled tests from the International Organization of Standardization (ISO) Technical Report 9790. Full scale tests were also conducted. For the ISO rating system, a dummy with a higher biofidelity rating responds much more like a human subject. The overall dummy biofidelity rating was determined to be "fair," at 4.6, an improvement over the SID and Eurosid-1 (which received ratings classifications of 2.3 and 4.4, respectively).

The agency also used the biofidelity ranking system developed by Rhule, et al., "Development of a New Biofidelity Ranking System for Anthropomorphic Test Devices," 2002, Stapp Car Crash Journal, Vol. 46, p. 477. The assessment included the dummy’s External Biofidelity (how much like a human the dummy loads the vehicle components) and Internal Biofidelity (how much like a human the dummy measures injury criteria measurement responses and is calculated for those body regions that have an associated injury criterion). The Overall External and Internal Biofidelity ranks are an average of each of the external and internal body region ranks, respectively. A lower biofidelity rank indicates a more biofidelic dummy. A dummy with an External Biofidelity rank of less than 2.0 responds much like a human subject. The ES-2re dummy had an Overall External Biofidelity rank of 2.6, compared to 2.7 for the ES-2 and 3.8 for the SID-H3. Its overall internal biofidelity rank was 1.6.

The ES-2re dummy’s repeatability and reproducibility were determined on the basis of component tests and sled tests of the two dummies. The component tests were conducted on head, neck, shoulder, upper rib, middle rib, lower rib, abdomen, lumbar spine and pelvis body regions. The repeatability assessment was made in terms of percent CV (Coefficient of Variance). A CV value of less than 5 percent is considered excellent, 5-8 percent good, 8-10 percent acceptable, and above 10 percent unacceptable. Nine tests were performed with one of the dummies, and 7 tests were performed with the other. The reproducibility was established by comparing the average responses of both dummies. The reproducibility assessment was made in terms of response differences between the two dummies with respect to the mean. A difference of less than 5% is considered excellent, 5-8% good, 8-10% acceptable, and above 10% unacceptable. The results of the tests indicate "excellent" repeatability and reproducibility ratings for all components except for the pelvis, which has a "good" rating. For a complete discussion of these tests, interested persons should consult the technical paper entitled "Technical Report—Design, Development and Evaluation of the ES-2re Side Crash Test Dummy," which has been placed in the agency’s docket.

In assessing the suitability of a dummy for side impact testing, it is necessary to consider its injury assessment capabilities relative to human body regions at risk in the real world crash environment. Crash data indicate that FMVSS No. 214 should encourage vehicle designs that protect not only an occupant’s head, but also other body regions in the vehicle-to-pole test. Accordingly, injury criteria are being proposed for the head, thorax, abdomen, and pelvis. A technical report titled, "Injury Criteria for Side Impact Dummies," and the agency’s Preliminary Economic Assessment for this NPRM, have a full discussion of these injury criteria and supporting data. (Both documents are available in the docket.)

The types of injury criteria proposed by NHTSA are generally consistent with those developed by ECE/WP.29, by the European Union in its directive EU 96/27/EC, and by EuroNCAP for rating vehicles, although some may differ, based upon the results of NHTSA testing. Four of NHTSA’s proposed injury criteria are specified in EU 96/27/EC for use with the EuroSID-1 dummy. NHTSA has tentatively decided not to use the chest viscous injury criteria, V*C £ 1.0. NHTSA has not found the V*C criterion to be repeatable and reproducible in the agency’s research.

While the ES-2 is an upgraded EuroSID-1 dummy, rather than an entirely new dummy, we have concluded that the thorax of the ES-2 is so different from that of the predecessor dummy that previously-generated EuroSID-1 data should not be considered in analyzing the ES-2 and its associated thoracic injury criteria. The flat topping and other problems of the EuroSID-1 make those earlier data of little value to researchers in analyzing the ES-2. Consequently, in developing the criteria discussed below, NHTSA limited its analysis to existing ES-2 data and our own research conducted with the ES-2re. The agency believes that these two data sets are interchangeable, except for ES-2 data affected by the back plate problem. Based upon our assessment of these dummies, we believe that the ES-2 with rib extension modifications is superior to the unmodified version. Accordingly, the agency is proposing use of the ES-2re with the following injury criteria.

Head:  NHTSA is proposing to require passenger cars and LTVs to limit HIC to 1000 (measured in a 36 millisecond time interval) when the ES-2re dummy is used in the proposed 32 km/h (20 mph) oblique vehicle-to-pole test (and the MDB test). This measure has been chosen because the HIC36 1000 criterion is consistent with the optional pole test designed to afford head protection under FMVSS No. 201. The HIC36 1000 criterion provides a measure with which the agency and the industry already have experience. HIC36 1000 relates to a 52 percent risk of AIS 3+ injury.

Thorax (Chest):  NHTSA has proposed two criteria to measure thoracic injury when using the ES-2re. First, chest deflection shall not be greater than 42 mm (1.65 in) for any rib (reflecting an approximate 50 percent risk of an AIS3+ injury). We note that our proposed requirement is harmonized with the EU regulation for the EuroSID-1. [33] However, the agency is also considering, and seeking comment on, an alternative chest deflection criterion within the range of 35 - 44 mm (1.38 – 1.73 in). This range corresponds to an approximate 40-50 percent risk of AIS3+ injury. Second, resultant lower spine acceleration shall not be greater than 82 g’s (reflecting a 50 percent risk of an AIS3+ injury).

The agency believes that a combination of the two criteria is appropriate to provide thoracic injury protection to vehicle occupants. NHTSA tentatively selected these two criteria based upon a series of 42 side impact sled tests using fully instrumented human cadaveric subjects and 16 sled tests using the ES-2re conducted at the Medical College of Wisconsin.  NHTSA conducted the analysis using logistic regression with injury outcome in cadaveric sled tests as the response, and ES-2 dummy measured physical parameters (maximum rib deflections, TTI, maximum spinal accelerations) in similar sled tests as the covariates. The subjects’ anthropometric data such as age, gender, and mass were also included as covariates since the agency believed that they might influence injury outcome. [34] This method of analysis provided injury criteria that can directly be applied to the ES-2re dummy.

Chest deflection has been shown to be the best predictor of thoracic injuries in low-speed crashes. We believe it to be a better injury risk measure than TTI(d) for the ES-2re dummy. [35] We added spinal acceleration criteria because we believe that there might be injurious loading conditions that are not picked up by the rib deflections measured on the ES-2re dummy, and spinal accelerations are a good measure of the overall load on the thorax. The acceleration at the lower spine ("lower spine acceleration") is also a measure that is less sensitive to direction of impact. Consequently, in concert, the two thoracic criteria will enhance injury assessment in a vehicle side crash test, and we expect them (and their associated reference values) to result in reduced chest injuries as compared to the criteria in the current standard.

While we have tentatively selected 42 mm as the deflection criterion, we are also considering a chest deflection limit within the range of 35 - 44 mm (1.38 – 1.73 in). NHTSA reanalyzed the Eppinger data set that was used when NHTSA undertook the rulemaking adopting the MDB test into FMVSS No. 214 in 1990 (see preceding footnote concerning TTI(d)). The agency analyzed the injury risk curve versus TTI(d) and estimated that a rib deflection of 44 mm (1.73 in) for the ES-2re would be approximately equivalent to a TTI(d) of 85 g’s for the SID. [36] (A TTI(d) limit of 85 g's is specified in the MDB test of FMVSS No. 214 for 4-door vehicles.)  The 44 mm (1.73 in) value corresponds to a 50 percent risk of injury for a 45-year-old occupant. [37] Data from NASS indicates that chest is still the predominant seriously injured body region and that serious chest injuries are prevalent in the modern vehicle fleet. A deflection limit of 35 mm, reflecting a 40 percent risk of an AIS 3+ injury, could markedly improve the chest protection afforded by FMVSS No. 214.

The proposed limit for resultant lower spine acceleration would be 82 g. The upper and lower spine of the ES-2re are instrumented with tri-axial accelerometers (x, y, and z direction corresponding to anterior-posterior, lateral medial, and inferior-superior). In purely lateral loading, one would expect only lateral (y) accelerations. Moreover, due to constraints built into their designs, the dummies exhibit predominantly y (lateral) acceleration due to lateral loading. In the side impact sled tests at the Medical College of Wisconsin (MCW), described above, the dummy’s lower spine accelerations were almost the same as the resultant acceleration (sqrt(x2+y2+z2)) since x and z accelerations are small. However, due to the complex response of humans, vehicle occupants experience x, y, z accelerations even in pure lateral loading. In vehicle crashes, loading can be in various directions. Therefore, NHTSA believes that to account for overall loading, resultant accelerations should be considered rather than lateral acceleration alone.

Abdomen:  The ES-2re dummy offers abdominal injury assessment capability, a feature that is not present in the SID dummy. The agency is proposing an abdominal injury criterion of 2,500 Newtons (N) (562 pounds). We note that our proposed requirement is harmonized with the abdominal load injury criterion used in the European side impact regulation, EU 96/27/EC, as well as the EuroNCAP Program for the EuroSID-1.  However, the agency is also considering, and seeking comment on, an alternative abdominal injury criterion within the range of 2,400 – 2,800 N (540 – 629 pounds). This range corresponds to an approximate 30-50 percent risk of AIS 3+ injury. The proposed abdominal injury criterion was developed using cadaver drop test data from Walfisch, et al. (1980). [38] Analysis of this data indicated that applied force was the best predictor of abdominal injury, and an applied force of 2,500 N (562 pounds) corresponds to a 33 percent risk of AIS 3+ injury. The MCW sled test data indicated that the applied abdominal force on the cadavers was approximately equal to the total abdominal force in the ES-2re dummy under similar test conditions.

This abdominal capability of the ES-2re is a potentially significant advantage over the SID dummy, and requiring vehicles to satisfy this injury criterion to meet FMVSS No. 214 might reduce the number of abdominal injuries to the driving population. In a NASS study of side impact crashes, it was estimated that between 8.5 percent and 21.8 percent of all AIS 3+ injuries are to the abdomen of restrained near side front seat occupants. [39] The SID dummy currently used in FMVSS No. 214 does not have these detection capabilities, thus leaving a gap in the control of injury outcomes in side crashes.

Pelvis:  NHTSA is proposing a pelvic force limit of not greater than 6,000 N (1,349 pounds) (25 percent risk of AIS3+ injury). The ES-2re has two pelvic measurement capabilities. First, the ES-2re has instrumentation to measure pelvic acceleration, as does the SID dummy. However, unlike the SID, the ES-2re is also capable of measuring the force (load) at the pubic symphysis, which is the region of the pelvis where the majority of injuries occur. A field analysis of 219 occupants in side impact crashes by Guillemot, et al. (1998) showed that the most common injury to the pelvis was fracture of the pubic rami (pelvic ring disruption). [40] Pubic rami fractures are the first to occur because it is the weak link in the pelvis.

This NPRM would only limit pubic symphysis force. The agency is not proposing an acceleration-based criterion because the agency believes that an injury threshold limit on pelvic acceleration is dependent on the impact location and the type of loading (distributed versus concentrated). Therefore, pelvic acceleration is not as good a predictor of pelvic fracture as force. The scientific literature has documented that force alone is a good predictor of pelvic injury. [41] Further, the pubic symphysis load injury criterion has been applied in the European side impact regulation EU 96/27/EC as well as the EuroNCAP Program, so there is experience with this measure and some demonstration of its usefulness. The criterion in those programs is 6,000 N (1,349 pounds), the same limit that we are proposing here.

The proposed injury criteria and limits are summarized below in Table 2:

Table 2: Proposed Injury Criteria for ES-2re
Criterion HIC36 Rib-Def. (mm) Lower Spine (g) Abd.-Force (N) Pubic-Force (N)
Proposed Limits 1,000 35-44* 82 2,400-2,800* 6,000
*A particular value within this proposed range would be selected.

NHTSA has conducted four 32 km/h (20 mph) oblique pole tests using the FMVSS No. 214 seating procedure and the ES-2re dummy. The agency has conducted five additional tests using the FMVSS No. 201 seating procedure. The first four tests were with the ES-2 dummy and the fifth test was with the ES-2re dummy. The test results are presented in Table 3.


Table 3. 75-Degree Pole Test Results
ES-2 Dummy or ES-2re Dummy
(Using FMVSS No. 214 Seating Position)
Test Vehicle Restraint* HIC36 Rib-Def.
(mm)
Lower Spine
(g)
Abd.-Force
(N)
Pubic-Force
(N)
Proposed Limits   1,000 35-44 82 2,400-2800 6,000
1999 Volvo S80** AC+Th 329 48.7 51.2 1,550 1,130
2000 Saab 9-5** Comb. 171 49.4 49.0 1,370 1,730
2004 Honda Accord** AC+Th 446 30.7 51.7 1,437 2,463
2004 Toyota Camry** AC+Th 452 43.4 52.5 1,165 1,849
Test Results Using FMVSS No. 201 Seating Position
1999 Nissan Maxima Comb. 5,254 35.7 45.1 1,196 2,368
1999 Volvo S80 AC+Th 465 40.7 51.4 1,553 1,700
2000 Saab 9-5 Comb. 243 49.9 58.3 1,382 2,673
2001 Saturn L200 AC 670 52.3 78.2 1,224 2,377
2002 Ford Explorer** AC 629 43.0 98.4 2,674 2,317
* Comb.=combination head/chest SIAB; AC=air curtain; Thorax or Th=chest SIAB
**Test was conducted with the ES-2re dummy.

Table 3 shows that vehicles with air curtain systems performed well in protecting the dummy’s head. The head/chest side air bag of the 2000 Saab 9-5 also passed the limit on HIC. However, the head/chest side air bag of the 1999 Nissan Maxima did not perform well (the HIC score was 5,254).

The agency’s tests of the Maxima illustrate how the impact angle of the pole test can influence the level of protection provided by a vehicle’s side air bags. NHTSA conducted three oblique pole tests using a Maxima without a side bag for the purpose of demonstrating test repeatability of the oblique pole test procedure. As previously mentioned, the HIC score for a Maxima vehicle with a head/chest side impact air bag was 5,254 (results presented in Table 3, above), while the HIC scores for Maxima cars without a side air bag head protection system ranged from 11,983 to 15,591. Although the combination side impact air bag system in the Maxima reduced the HIC by up to 66 percent to 5,254, the HIC level was nevertheless high enough to have caused fatal injuries. On the other hand, the results of the test of the Maxima vehicle in a 90-degree FMVSS No. 201 pole test (Table 6, infra) showed successful results with a HIC score of 130.

The 75-degree impact produces a different dummy head trajectory. Judging from the film coverage of the Maxima test, in the oblique pole test, the combination SIAB in the Maxima did not prevent the occupant head from rotating into the pole. [42]   In order to comply with the proposed oblique pole test requirements, NHTSA expects that manufacturers will install head protection systems extending sufficiently toward the A-pillar to protect the head in the 75-degree approach angle test. Further, the proposed 32 km/h (20 mph) oblique pole test has a lateral component of 31 km/h (19.3 mph). Thus, it has at least 15 percent [43] more kinetic energy than the FMVSS No. 201 90-degree pole test at 18 mph.

In the four tests using the FMVSS No. 214 seating position, the ES-2re rib deflection exceeded the maximum deflection in the proposed range (i.e., 44 mm or 1.73 in) in half of the vehicles tested. The ES-2re rib deflection was exceeded in both tests of the 1999 Volvo and 2000 Saab vehicles. All of the vehicles in this series were equipped with thorax air bags of some type. Of the two vehicles that met the rib deflection criteria, the 2004 Toyota Camry test was very close to the proposed upper 44 mm (1.73 in) limit with a rib deflection of 43.4 mm (1.71 in). However, the other vehicle, the 2004 Honda Accord, met the lowest proposed rib deflection criteria with more than 4 mm to spare. Thus, the Accord demonstrates the practicability of meeting the proposed requirements using the FMVSS No. 214 seating procedure.

In the five tests using the FMVSS No. 201 seating position, the ES-2 rib deflection exceeded the proposed upper limit of 44 mm (1.73 in) in one of the two vehicles equipped with air curtains and no separate chest air bag (Saturn L200). The ES-2 rib deflection was also exceeded in one vehicle equipped with a combination head/chest side air bag (Saab 9-5). The three remaining vehicle tests (Nissan Maxima, Ford Explorer, and Volvo S80) did not result in rib deflection readings above the proposed  upper limit. The Ford Explorer did, however, exceed the limits on lower spine acceleration and abdominal force, which might have been partially due to the fact that the vehicle only had an air curtain system and no thorax air bag. (See Table 3.)


NHTSA believes that the ES-2re and the SID-H3 would yield similar benefits in head protection. Of the two, NHTSA prefers the ES-2re for its overall superior biofidelity and additional injury assessment capability.

In comparing the biofidelity of the two dummies, the ISO and other researchers (Rhule, et al., 2002) found that the ES-2re dummy demonstrates more human-like response than the SID-H3 in virtually every category examined. [44]

The agency believes that more effective and encompassing test tools should be used to assess the effectiveness of side impact countermeasures, particularly those involving head air curtains and either seat or door mounted air bags. The ES-2re, with the more human-like rib cage geometry, mass distribution, and telescopic rib compression mechanism, provides the capability of measurement of chest compression. It also has an abdomen that is a weighted deformable element with internal load cells to measure load transfer through to the spine. Given that abdominal injuries constitute up to 20 percent of all injuries in side impact, it is desirable that an ATD can assess this injury. Of lesser significance, but still of importance, is the ES-2re dummy’s instrumentation of the pelvis. Besides acceleration, it permits the measurement of force through the iliac wing to the sacrum and pubic symphysis. [45]

However, as noted above, NHTSA is considering using the SID-H3, particularly if all of the injury measures available in ES-2re are not adopted in FMVSS No. 214. The SID-H3 has been used for years in the optional vehicle-to-pole test in FMVSS No. 201 and is acceptably biofidelic as a test device. While SID-H3 is not as advanced an ATD as the ES-2re, it can measure head acceleration and is still an improvement over the SID. HIC would be limited to 1,000 as it is now in FMVSS No. 201. TTI and pelvic acceleration would be limited as they are now specified for the SID in the MDB test. TTI(d) would have an 85g limit for 4‑door vehicles and a 90g limit for 2‑door vehicles. The pelvic acceleration would be limited to 130g.

NHTSA has conducted three oblique pole tests with the SID-H3 dummy using the FMVSS No. 201 seating procedure. Table 4 shows that all three vehicles tested with the SID-H3 dummy would not comply with one or more of the proposed injury criteria in that test.


Table 4. 75-Degree Oblique Pole Test Results (SID-H3 Dummy)
(Using FMVSS No. 214 seating position)
Test Vehicle Restraint* HIC36 TTI(d) Pelvis-g
Proposed Limits   1,000 85/90 (4-door/2-door) 130
1999 Volvo S80 AC+Th 395  49.0 59.1
2000 Saab 9-5 Comb. 182 77.0 82.1
Using FMVSS No. 201 seating position
1999 Volvo S80 AC+Th 2,213 57.0 55.7
2000 Saab 9-5 Comb. 5,155 90.5 80.4
2002 Ford Explorer AC 330 105.0 81.3
* Comb.=head/chest SIAB; AC=air curtain; Th=chest SIAB

The results of the first oblique pole test using the FMVSS No. 201 seating position exceeded the HIC-1000 criterion, the last test exceeds the TTI(d)-85 criterion, and the second test exceeded both the head and the chest injury criteria. The 1999 Volvo S-80 exceeded the HIC-1000 requirement by 1,213. In this oblique pole test with the SID-H3, using the FMVSS No. 201 seating procedure, the SID-H3’s head contacted a joint area of the air curtain and the tether hardware. The air curtain apparently was not large enough to prevent a partial head-to-pole contact. In contrast, in the 90-degree pole test shown in Table 7, infra, of a Volvo S-80, the SID-H3’s HIC score was 237. The HIC score of the SID-H3 in the oblique Saab test was 5,155. In the oblique pole test of the Saab, the SID-H3’s head partially contacted the front upper edge of the combination head/chest air bag and then rotated into the pole. These HPS designs would likely need to be changed if an oblique pole test were adopted, and the SID-H3 dummy were used, to expand the contact area covered to prevent the SID-H3 dummy head from rotating into the pole.

It should be noted that when the aforesaid two tests were repeated using the FMVSS No. 214 seating procedure, the HIC scores were dramatically lower. Compared to the FMVSS No. 201 seating position, the FMVSS No. 214 seating position can place the dummy rearward and closer to the B-pillar. Since the production HPS was wide enough to cover the dummy head trajectory in this seating position, the HIC values were significantly lower.


NHTSA’s analysis of side impact crash data found that nearly 35 percent of all MAIS 3+ injuries in near-side, non-rollover, tow-away side crashes occurred to small stature occupants (between 56 – 64 inches or 142 – 163 cm in height). Most of these (93 percent) were female. Id. The 1990-2001 NASS/CDS data also indicate that there are differences in the body region distribution of serious injuries between small and medium stature occupants that are seriously injured in these side collisions. The data suggests that small stature occupants have a higher proportion of head, abdominal and pelvic injuries than medium stature occupants, and a lesser proportion of chest injuries.

The SID-IIs 5th percentile female dummy has a mass of 44.5 kg (98 pounds) and a seated height of 790 mm (31.1 inches). The dummy is capable of measuring forces to the head, neck, shoulder, thorax, abdomen and pelvis body regions and measures compression of the thoracic region. [46]  NHTSA proposes to use a modified version of the dummy in the oblique pole test to improve the real world protection of small stature occupants in side impacts.


The development of a small, second generation side impact dummy was undertaken in 1993 by the Occupant Safety Research Partnership (OSRP) under the umbrella of the U.S. Council on Automotive Safety Research. There was a need for an ATD that would be better suited to help evaluate the biomechanical performance of advanced side impact countermeasures, notably air bags, for occupants that are smaller than the 50th percentile size male. Data from frontal testing for similar air bag exposures indicated that smaller dummies were generally subjected to higher loadings than the 50th percentile male dummies. The new dummy was named SID-IIs indicating "SID" as side impact dummy, "II" as second generation, and "s" as small. The OSRP completed the development of the SID-IIs as a beta prototype in late 1998.

The dummy was extensively tested in the late 1990s and early 2000 in vehicle crashes by Transport Canada, and to a limited extent by U.S. automobile manufacturers and suppliers and the IIHS. NHTSA began an extensive laboratory evaluation of the dummy in 2000. Initial testing revealed chest transducer mechanical failures and some ribcage and shoulder structural problems. NHTSA’s Vehicle Research and Test Center modified the dummy’s thorax in 2001 to incorporate floating rib guides ("FRG") to better stabilize the dummy’s ribs. It was visually observed in abdominal-loading sled tests of the SID-IIs that the ribs did not stay in place in some of the tests, which raised concerns regarding the accuracy of the acceleration and deflection measurements, as well as the durability of the ribs and the deflection potentiometers. NHTSA modified the shoulder and rib guide design to remove excessive vertical rib motion. A detailed discussion of these modifications is provided in a technical report entitled, "Development of the SID-IIs FRG," Rhule and Hagedorn, November 2003, that has been placed in the docket for this NPRM.

NHTSA expects to publish a proposal to incorporate the specifications and calibration procedures for the 5th percentile female dummy in Part 572 in 2004. The agency has placed a technical report and other materials describing the dummy, as modified by NHTSA with floating rib guides, in the Docket for today’s NPRM. The SID-IIs is well-known to industry and researchers since it has been produced and used for about 5 years and is extensively used by Transport Canada, by IIHS in its consumer ratings program of vehicles’ side impact performance with a moving barrier, and by industry to meet industry standards with respect to the safety performance of side air bags and with respect to the risks of side air bags to out-of-position children and small adults.

Biofidelity.   The Small Sized Advanced Side Impact Dummy Task Group of the OSRP evaluated the SID-IIs Beta-prototype dummy against its previously established biomechanical response corridors for its critical body regions. (Scherer, et al., "SID IIs Beta+-Prototype Dummy Biomechanical Responses," 1998, SAE 983151.)  The response corridors were scaled from the 50th percentile adult male corridors defined in an ISO Technical Report 9790 to corridors for a 5th percentile adult female, using established ISO procedures. Tests were performed for the head, neck, shoulder, thorax, abdomen and pelvis regions of the dummy. Testing included drop tests, pendulum impacts and sled tests. The biofidelity of the dummy was calculated using a weighted biomechanical test response procedure developed by the ISO. The overall biofidelity rating of the SID-IIs beta+-prototype was 7.0, which corresponds to an ISO classification of "good." Id.

The agency also used the biofidelity ranking system developed by Rhule, et al., 2002, supra, to assess the biofidelity of the SID-IIs with FRG hardware. (See "Biofidelity Assessment of the SID IIsFRG dummy," a copy of which has been placed in the docket.)  The assessment included the dummy’s External Biofidelity and Internal Biofidelity. The SID-IIsFRG dummy displayed Overall External Biofidelity comparable to that of the ES-2re. The SID-IIsFRG provided improved biofidelity over the SID-H3 in all body regions except for the head/neck. The Overall Internal Biofidelity ranks of the SID-IIsFRG are all better than those of the other dummies, with the exception of the "without abdomen and with TTI" rank. All body region Internal Biofidelity ranks were better than, or comparable to, those of the ES-2re, ES-2 original, and SID-H3, except for the Thorax-TTI, which had a rank of 2.9. However, the SID-IIsFRG dummy is a deflection-based design and is not expected to rank well in this parameter. Even with an Internal Thorax-TTI rank of 2.9 included in the Overall rank (without abdomen), the SID-IIs Internal Biofidelity rank (1.6) is equivalent to that of the ES-2re (1.6) and better than that of the SID-H3 (1.9).


Injury criteria are being proposed for the head, lower spine and pelvic regions. A complete discussion of these injury criteria and supporting data can be found in NHTSA’s research paper, "Injury Criteria for Side Impact Dummies," and the Preliminary Economic Assessment, which have been placed in the Docket for this NPRM.

Head: The head injury criterion (HIC) shall not exceed 1000 in 36 ms, when calculated in accordance with the equation specified in S7 of FMVSS No. 201. This measure has been chosen for the reasons discussed with respect to the ES-2re, supra.

Thorax (Chest):  The agency is not proposing a limit on chest deflection at this time. The agency would like to obtain more data on the dummy’s rib deflection measurement capability under oblique loading conditions before proceeding with a proposal limiting such deflections in oblique side impact tests. Further assessment of the injury criteria applied to the SID-IIsFRG is also needed. NHTSA will continue to monitor rib deflections in tests using the SID-IIsFRG for further consideration.

NHTSA is proposing that the resultant lower spine acceleration must be no greater than 82 g. The resultant lower spine acceleration is a measure of loading severity to the thorax. In vehicle crashes, loading can be in various directions. Therefore, NHTSA believes that to account for overall loading, resultant accelerations should be considered rather than lateral acceleration alone. Though dummy-measured accelerations for the level of loading severities experienced in vehicle crashes might not have a causal relationship to injury outcome, they are good indicators of thoracic injury in cadaver testing and overall loading to the dummy thorax.

NHTSA selected the criterion based upon the series of 42 side impact sled tests using fully instrumented human cadaveric subjects, previously discussed, conducted at the MCW as well as sled tests conducted with the SID-IIs dummy under identical impact conditions as the cadaveric sled tests. The agency believes that the age of the subject involved in a side impact affects injury outcome. Subject age in the MCW sled test data was found to have significant influence on injury outcome and so was included in the injury models. The resulting thoracic injury risk curves were normalized to the average age of the injured population in a side impact crash that is represented by the SID-IIs dummy. The average age of AIS 3+ injured occupants less than 1,63 cm (5 feet 4 inches) involved in side impact crashes with no rollovers or ejections was 56 years based on NASS-CDS files for the year 1993-2001. Therefore, thoracic injury risk curves were normalized to the average occupant age of 56 years.

However, the agency’s research has found that the resultant lower spine acceleration might over-predict injury risk at certain levels, or in other words, have a high "false positive" rate. Consequently, the agency selected a conservative resultant lower spine acceleration limit of 82 g to ensure a low false positive rate of approximately 5 percent. This corresponds to an approximate 60 percent risk of AIS 3+ injury. While this risk level is notably higher than that being proposed for the 50th percentile male dummy, the agency also balanced the SID-IIsFRG injury criteria with the practicability of vehicles being able to meet the proposed requirements. For example, if the agency were instead to consider a 50 percent AIS 3+ injury risk (as proposed for the 50th percentile male dummy) the corresponding lower spine acceleration limit would be approximately 62 g. Based on our limited testing to date (see Table 5), we believe this limit would be too low for vehicles to practicably meet. Therefore, we believe our proposal of 82 g strikes a good balance. The agency recognizes that there are construction differences in the spine box between the ES-2re and the SID-IIs. NHTSA plans to continue testing these dummies in vehicles and monitor the differences in lower spine responses, if any.

Pelvis and Abdomen: As presented in the report "Injury Criteria for Side Impact Dummies," the pelvic injury criterion was developed from an analysis of the same cadaver impact data that was used for the development of the ES-2re pelvic injury criterion. The measured loads in these impact tests were distributed over a broad area of the pelvis that included the iliac crest and the greater trochanter. [47] The measured applied pelvic force to the cadaveric subjects was mass-scaled to represent the applied forces on a 5th percentile female. Under similar impact conditions, the scaled applied pelvic forces on the cadaveric subjects was assumed to be equal to the sum of the iliac and acetabular forces measured on the SID-IIsFRG dummy. [48]  Therefore, the pelvic injury risk curves developed for the SID-IIsFRG dummy are based on the maximum of the sum of the measured acetabular and iliac force. The proposed 5,100 N force level for the SIDIIsFRG corresponds to a 25 percent risk of AIS 3+ pelvic fracture. [49]

As with the SID-IIsFRG rib deflection instrumentation, the agency would like to obtain more data on the dummy’s abdominal measurement capability under oblique loading conditions before proceeding with a proposal limiting such deflections in oblique side impact tests. Data on abdominal deflection and other measures will continue to be monitored by NHTSA in all future tests using the SID-IIsFRG dummy.


NHTSA has conducted three oblique pole tests with the SID-IIsFRG dummy seated in the full forward position. The test results are presented in the following Table 5:


Table 5. 75-Degree Pole Test Results
(SID-IIsFRG Dummy)
Test Vehicle Restraint* HIC36 Lower
Spine (g)
Pelvis (N)
Proposed Limits   1,000 82 5,100
2003 Toyota Camry (tested April 2003) AC+Th (remotely fired at 11 ms) 512 70 4,580
2003 Toyota Camry (tested March 2003) AC+Th (bags did not deploy) 8,706 78 5,725
2000 Saab 9-5 Comb. 2,233 67 6,045
2002 Ford Explorer AC (remotely fired at 13 ms) 4,595 101 7,141
*Comb.=head/chest SIAB; AC=air curtain; Th=chest SIAB

These data indicate that the most serious problem in terms of protecting small occupants in oblique crashes is lack of head protection. NHTSA believes that this can be resolved by providing an inflatable head protection system that has been re-designed to address small occupants. The practicability of this approach is illustrated by the results for the 2003 Camry (air curtain and thorax side air bag system) tested in April 2003 (HIC 512). In contrast, in a March 2003 test of the Camry in which the air curtain and thorax bags did not deploy, the SID-IIsFRG had a HIC of 8,706.

The agency’s Preliminary Economic Assessment for this NPRM estimates that the use of the SID-IIsFRG in the oblique pole test would save an additional 164 lives beyond the fatalities saved by changes to vehicle designs to meet an oblique pole test using the 50th percentile male dummy alone.


The agency is considering the possibility of using a 29 km/h (18 mph) 90 degree impact test, such as that incorporated into FMVSS No. 201’s pole test (or a 90 degree test conducted at a 32 km/h (20-mph) test speed). The 90 degree impact angle has proven itself repeatable and an acceptable way to ensure some level of performance of head protection systems in perpendicular, vehicle-to-narrow-object impacts. An advantage to having the impact angle and test speed be the same as that used in FMVSS No. 201 would be that inflatable head protection systems that are already in place in many vehicles would meet these criteria when tested in a 90-degree impact. Using the same test as is currently optional would possibly allow the installation of inflatable head protection systems in all vehicles faster and at lower cost. A disadvantage is that fewer lives would be saved. (NHTSA estimates that 446 lives would be saved by the FMVSS No. 201 test using the 50th percentile male dummy, while 792 lives would be saved by the oblique pole test using the 50th percentile male dummy. An estimate 859 lives would be saved by the oblique pole test using both the 5th percentile female dummy and the 50th percentile male dummy.)

NHTSA has conducted several 29 km/h (18 mph) 90-degree pole tests of vehicles equipped with either the combination head/chest SIAB or side window air curtain (AC) systems, using the ES-2 dummy. See Table 6.


Table 6. FMVSS No. 201 Pole Test 90-Degree Test Results
(ES-2 Dummy)
Test Vehicle Restraint* HIC36 Rib-Def.
(mm)
Lower Spine
(gs)
Abd.-Force
(N)
Pubic-Force
(N)
Proposed Limits   1,000 35-44 82 2,400-2,800 6,000
1999 Maxima Comb. 130 33.0 45.7 1,450 2,080
1999 Cougar Comb. 313 41.5 56.6   859 2.214
1999 Volvo S80 AC+Th 244 41.5 36.7 1,217 1,166
1999 Ford Windstar Comb. 164 31.4 53.5 2,352 1,382
2000 Saab 9-5 Comb. 114 37.8 40.2   849 1,733
2001 Saturn L200**            
2002 Ford Explorer AC 208 45.9 65.5 2,074 1,262
* ITS=inflatable tubular structure; Comb=combination head/thorax air bag; AC=air curtain; Th=chest SIAB
** Lateral back plate lateral load 2,047 N

Based on the test results using the ES-2 dummy, inflatable head protection systems appear to be working relatively well in protecting the occupant’s head in a perpendicular test. All HIC measurements were well below the 1,000 limit. The lower spine g’s and other force measurements were below the proposed limits. However, rib deflections exceeded the proposed 44 mm (1.73 in) upper limit in a test of a sport utility vehicle (SUV) (Ford Explorer) and a passenger car (Saturn L200) (both of which had no additional thorax protection, but just an air curtain for the head), and was close to the limit in tests of two other passenger cars. This suggests that if a 90-degree vehicle-to-pole test with an ES-2 dummy were added to FMVSS No. 214, it is likely that the installation of additional chest protection countermeasures would be needed in many production vehicles to comply with a rib deflection criterion in the range of 35-44 mm. [50]

All test results listed in Table 6 were from the ES-2 without the "rib extension" fix, in which back plate lateral loads were considered low (under 1000 N)(224.8 lb). As discussed earlier in this preamble, the agency has developed a fix (which consists of "rib extensions," a set of two needle bearings for each rib plus a Teflon coated back plate) to minimize or eliminate the grabbing force. The extended ribs provide a continuous loading surface that nearly encircles the thorax and enclose the posterior gap of the ES-2 ribcage. As such, for tests using the ES-2 without the fix in which there were large back plate loads, the rib extensions can result in increased rib deflections in the modified dummy since an intruding structure can no longer grab the dummy back plate without loading the rest of the thorax. As discussed in the agency’s technical report for the ES-2re dummy, the results of two 2002 Impala side NCAP tests show that the agency’s fix has reduced the grabbing force from 4.7 kN (989 pounds) to practically zero. The tests also show that the rib deflection increased from 16-24 mm (0.63-0.94 inches) to 43-51 mm (1.69-2.01 inches).

NHTSA believes that tests using the ES-2 without the fix in which there were small back plate loads reflect the likely performance of vehicles in tests with the ES-2re. Two sets of side NCAP tests were conducted using a 2003 Toyota Corolla and a 2001 Ford Focus. The results showed that the rib extension fix did not adversely affect the results when the back plate grabbing force was reported to be low in the original ES-2 design.

With regard to abdominal force in the FMVSS No. 201 pole tests, the abdominal force measurements were far below the 2,800 N (629 pound) proposed upper limit. However, the ES-2 dummy in the Ford Windstar and the Ford Explorer produced a significantly higher abdominal force than in the five passenger cars. These two vehicles, being relatively higher and heavier than passenger cars, can comply with those requirements relatively easily when tested with the MDB. However, as mentioned previously, a higher and heavier vehicle would not have much advantage, if any, over an average passenger car in the proposed pole test.

Since 1999, the agency has conducted eleven 29 km/h (18 mph) 90-degree pole tests using the SID-H3. Ten of these were in the agency’s compliance test program of FMVSS No. 201, and one was conducted for research purposes. The results are tabulated below in Table 7:


Table 7. FMVSS No. 201 Pole Test 90-Degree Test Results
(SID-H3 Dummy)
Test Vehicle Restraint* HIC36 TTI(d) Pelvis-g
Proposed Limits   1,000 85/90
(4-door/2-door)
130
1999 Volvo S80 AC+Th 237 36.0 44.0
1999 BMW 328i ITS+Th 340 47.0 49.0
2001 Saturn L200 AC 579 63.0 47.7
2001 Lexus GS-300 AC+Th 336 51.3 55.7
2001 VW Jetta AC+Th 444 38.0 40.5
2001 Mercedes C240 AC+Th 457 78.9 60.2
2002 Ford Explorer AC 183 83.0 48.0
2002 Mercedes C230 AC+Th 306 47.0 49.8
2002 Jaguar X-type AC+Th 271 46.6 44.3
2002 Saturn Vue AC 533 53.1 51.5
2003 Cadillac CTS AC+Th 281 45.8 46.6
* ITS=inflatable tubular structure; AC=air curtain; Th=chest SIAB

These test results indicate that inflatable head protection systems perform adequately in protecting an occupant’s head in a 90-degree impact. The HIC measurements are well below the 1,000 limit. In contrast, the 1999 BMW 328i and the 2001 Saturn L200, when tested without the HPSs (not shown), received HIC scores of 2,495 and 11,071, respectively. The pelvis accelerations in the above tests are also well below the 130 g’s allowable limit. Based on the above pole test data, NHTSA believes that the current production vehicles, when equipped with an inflatable head protection system, would comply with the proposed 90-degree pole test requirements if the tests were performed with a SID-H3 dummy (even assuming the FMVSS No. 201 seating position were used).

In general, the TTI(d) measurements are also low. Judging from the above limited test results, NHTSA believes that the safety countermeasures that have been installed in passenger cars to comply with existing FMVSS No. 214 requirements (i.e., the MDB side impact requirements (for the chest and the pelvis)) also provide significant protection in 90 degree, 29 km/h (18 mph) impacts against a rigid narrow object.

However, these tests indicate also that in vehicles with a greater riding height relative to the MDB, the dummy’s chest is loaded more severely in a pole test than in the standard’s MDB test. Thus, many LTVs would likely have a harder time in a pole test than in an MDB test in meeting the thoracic protection criteria of FMVSS No. 214. For example, the Ford Explorer did not comply with the TTI(d)-85g limit in the oblique pole test (Table 4). The Explorer barely met the TTI(d)-85g limit in a 90-degree test (Table 7). The Ford Explorer had a TTI(d) of 83 g's, approaching the TTI(d)-85g limit. As noted above, it is easier for an SUV to comply with the MDB test requirements because of the greater ride height and greater mass of the SUV relative to the MDB. (To illustrate, NHTSA tested the 2002 Ford Explorer in the side NCAP configuration with the MDB and the results showed that both the driver and the rear seat passenger received a low TTI(d) score of 35 g's.) 



[17] We propose excluding certain vehicles from the pole test: motor homes, tow trucks, dump trucks, ambulances and other emergency rescue/medical vehicles (including vehicles with fire-fighting equipment), vehicles equipped with wheelchair lifts, vehicles with raised or altered roof designs (see definitions in FMVSS No. 216, "Roof crush resistance"), and vehicles which have no doors, or exclusively have doors that are designed to be easily attached or removed so that the vehicle can be operated without doors. Many vehicles within these categories tend to have unusual side structures that are not suitable for pole testing or have features, such as a lowered floor or raised roof, which could pose practicability problems in meeting the test. Comments are requested as to whether these vehicles should be excluded from only the HIC requirement or from both head and thoracic protection in the pole test. Comments are also requested on the need to exclude other types of vehicles from the pole test, such as convertibles that lack a roof structure enabling the installation of an air curtain. Suggestions that NHTSA exclude certain vehicle types should include information supporting the exclusion and a discussion of the extent of the exclusion (e.g., from only the limit on HIC and not the limits on the other injury criteria of this proposal).

[18] The lateral component of the velocity would increase only 1.3 mph and not 2 mph.

[19] The pole test is very similar to the proposed International Organization for Standardization (ISO) test procedure found in the ISO/TC22/SC10/WG3 draft ISO Technical Report, "Road Vehicles, Dynamic Side Impact Crash Test Procedure for Evaluating Occupant Interactions with Side Airbags for a Pole Impact Simulation (ISO/CD 15829, February 9, 1995), with differences noted below

[20] This NPRM proposes to refine how the vehicle test attitude is determined. Currently, the vehicle attitude is defined by measurements made from the ground (a level surface) to a reference point placed on the vehicle body above each of the wheels. These measurements are made with the vehicle in the "as delivered," "fully loaded," and "pre test (or as -tested)" conditions. This NPRM proposes that the method used to determine the test attitude be revised to align with that used in S13.3 of FMVSS No. 208. In that provision (specifying test procedures for a sled test), a test attitude is determined based on door-sill angle measurements to control the vehicle's pitch attitude. This NPRM also proposes to define the vehicle's roll attitude by a left to right angle measured along a fixed reference point at the front and rear of the vehicle at the vehicle longitudinal center plane. We have placed in the docket for comment a document setting forth the test procedures the agency is developing for the test.

NHTSA is proposing these changes because we believe that measuring the angles more directly, better facilitates and more accurately determines the vehicle attitudes than by use of the method in current S6.2 of FMVSS No. 214 (specifying test procedures for the MDB test). NHTSA also proposes to use the new method to define the vehicle test attitude for the MDB test. In the MDB test, the dummy and vehicle instrumentation, high-speed cameras, associated brackets and instrumentation umbilical lines that are added to the vehicle make it difficult sometimes to achieve the corridor between the as delivered and fully loaded attitudes, particularly at the right front position of the vehicle. (The agency also requests comments on keeping the present method used to determine vehicle test attitude, but adding a ± 10 mm tolerance.)

[21] Under the FMVSS No. 201 seating procedure, the dummy’s head is positioned such that the point at the intersection of the rear surface of its head and a horizontal line parallel to the longitudinal centerline of the vehicle passing through the head’s center of gravity is at least 50 mm (2 inches) forward of the front edge of the B-pillar. If needed, the seat back angle is adjusted, a maximum of 5 degrees, until the 50 mm (2 inches) B-pillar clearance is achieved. If this is not sufficient to produce the desired clearance, the seat is moved forward to achieve that result.

[22] However, that huge difference was not present in tests of the 1999 Volvo with the ES-2 dummy. Tested obliquely, the Volvo achieved a HIC of 465; in a 90-degree test, the HIC was 244.

[23] Simply using a 5th percentile female dummy in addition to a 50th percentile male dummy in a 90-degree pole test might not result in seat-mounted head/thorax bags being wider. The two dummies would be positioned fore-and-aft and horizontally at different places in the vehicle. However, if the HPS were seat-mounted, the seat-mounted HPS would travel along the seat track with the dummies. That HPS could be tuned to a 90-degree pole test and not provide benefits in an oblique impact.

[24] About 60 percent of the partial ejections occurred to belted occupants.

[25] While the shoulder of the SID-H3 could interfere with the chest reading in the perpendicular test, FMVSS No. 201 does not specify chest injury criteria.

[26] NHTSA analyzed 1991-2000 NASS cases involving (1) AIS 3 and greater injured occupants in near side impacts, (2) non-rollover tow-away side crashes without complete ejections, and (3) occupants with a height of 1,422 mm (56 inches) or greater. There were a total of 1,965 cases: 1,073 male occupants, 891 female occupants, and one with unknown gender. The injury distribution was 775 fatalities and 1,190 seriously injured. These cases were annualized to national estimates. The analysis was performed with respect to three parameters - (1) gender (male and female), (2) body heights (short, medium, and tall categories), and (3) MAIS 3 and greater injured body regions (head, chest, abdomen, and others). ("Medium height" was the middle of all occupant height/weight as studied.)

[27] The Alliance of Automobile Manufacturers, the Association des Constructers Europeens d’Automobiles and the Japan Automobile Manufacturers Association wrote an October 16, 2002 letter to NHTSA urging the agency to "actively participate in the final development of WorldSID with the intention of specifying this device in a future upgrade to FMVSS 214."  NHTSA supports the continuous improvement of test dummies. However, the agency will not delay this rulemaking to wait for the WorldSID. In the agency’s best estimate, it will take a considerable amount of time to complete the evaluation of the WorldSID for its usefulness in vehicle tests, to determine its ability to project the risk of occupant injury, and to implement its use into FMVSS No. 214 compliance testing. In contrast, based on worldwide use experience of the EuroSID-1 and considerable experience with the ES-2, the rulemaking to incorporate the ES-2re dummy into Part 572 can be initiated in 2004. Since the dummy is available now for use in side impact testing, we estimate that the ES-2re could serve the need for an upgraded anthropomorphic test device (ATD) until the final development and implementation of the WorldSID. This assumes, of course, that WorldSID would ultimately be found to be suitable for use in FMVSS No. 214 and that the agency would decide through notice-and-comment rulemaking that its use in compliance testing is appropriate.

[28] The preamble to NHTSA’s final rule adopting its current side impact dummy (SID) noted that the agency found that the EuroSID dummy had problems with flat topping. The agency stated, "[o]ne of the problems discovered in NHTSA’s EuroSID sled tests was that the ribs were bottoming out, which may have invalidated the V*C measurements being made. This condition was characterized by a flat spot on the displacement-time history curve, while the acceleration-time history curve showed an increase with time until the peak g was reached. Although considerable attempts were made to correlate V*C and TTI(d), the deflection data collected continue to be questionable."  55 FR 45757, 45765 (October 30, 1990).

[29] "Report to Congress: NHTSA Plan for Achieving Harmonization of the U.S. and European Side Impact Standards," April 1997; "Report to Congress: Status of NHTSA Plan For Side Impact Regulation Harmonization and Upgrade," March 1999. NHTSA Docket No. 1998-3935-1 and –10 of the DOT Docket Management System at www.dms.dot.gov/.

[30] V*C, viscous criterion, is another way of measuring thoracic injury. It is based upon the product of chest compression and the rate of compression.

[31] On March 11, 2002, Nissan made a presentation to NHTSA on sled test results that Nissan believed showed back plate loading in the ES-2. See Docket NHTSA-99-7381.

[32] The UN/ECE World Forum for Harmonization of Vehicle Regulations (WP.29) administers several agreements relating to the global adoption of uniform technical regulations. An agreement, known as the 1958 Agreement, concerns the adoption of uniform technical prescriptions for wheeled vehicles, equipment and parts and the development of motor vehicle safety regulations for application primarily in Europe. UN-member countries and regional economic integration organizations set up by UN country members may participate in a full substantive capacity in the activities of WP.29 by becoming a Contracting Party to the Agreement. Various expert groups (e.g., the GRSP) within WP.29 make recommendations to WP.29 as to whether regulations should be adopted by the Contracting Parties to the 1958 Agreement. Under the 1958 Agreement, new Regulations and amendments to existing Regulations are established by a vote of two-thirds majority of Contracting Parties. The new Regulation or amendment becomes effective for all Contracting Parties that have not noticed the Secretary-General of their objection within six months after notification.

[33] Based on an analysis of the limited thoracic force-deflection cadaver data available in the 1980’s, the U.S. Advisory Group of Working Group 6 of ISO indicated that a rib-to-spine deflection of 42 mm would correspond to a 50 percent risk of nine rib fractures. According to Dr. Tarriere from Renault, internal organ injuries and flail chest (AIS 4) would be more likely to occur if the number of rib fracture became higher than nine. Dr. Terriere indicated that we could exclude severe internal organ injuries by excluding the AIS 4 flail chest injury. Based on that reason, European groups concluded that the EuroSID-1 should be based on the risk of rib fractures and thus a rib deflection < 42 mm. It should be pointed out that the said rib deflection criterion is a cadaver–based injury criterion for lower AIS level injuries, and that no transformation was made between the EuroSID-1 and the cadaver test data.

[34] Kuppa, S., Eppinger, R., McKoy, F., Nguyen, T., Pintar, F., Yoganandan, Y., "Development of Side Impact Thoracic Injury Criteria and their Application to the Modified ES-2 Dummy with Rib Extensions (ES-2re), Stapp Car Crash Journal, Vol. 47, October, 2003.

[35]TTI(d), a chest acceleration-based criteria, when combined with anthropometric data, was developed by NHTSA (Eppinger, R. H., Marcus, J. H., Morgan, R. M., (1984), "Development of Dummy and Injury Index for NHTSA’s Thoracic Side Impact Protection Research Program," SAE Paper No. 840885, Government/Industry Meeting and Exposition, Washington, D.C.; Morgan, R.M., Marcus, J. H., Eppinger, R. H., (1986), "Side Impact – The Biofidelity of NHTSA’s Proposed ATD and Efficacy of TTI," SAE Paper No. 861877, 30th Stapp Car Crash Conference) and is included in the FMVSS No. 214 side impact protection standard.

[36] Kuppa, S., Eppinger, R., McKoy, F., Nguyen, T., Pintar, F., Yoganandan, Y., "Development of Side Impact Thoracic Injury Criteria and their Application to the Modified ES-2 Dummy with Rib Extensions (ES-2re), Stapp Car Crash Journal, Vol. 47, October, 2003.

[37] Logistic regression analysis using cadaver injury and anthropometry information along with the ES-2 measurements indicate that the age of the subject at the time of death had a significant influence on the injury outcome (p<0.05). Id.

[38] Walfisch, G., Fayon, C., Terriere, J., et al., "Designing of a Dummy’s Abdomen for Detecting Injuries in Side Impact Collisions, 5th International IRCOBI Conference, 1980.

[39]   Samaha, R.S., Elliot, D., "NHTSA Side Impact Research: Motivation for Upgraded Test Procedures," Proceedings of the 18th Enhanced Safety of Vehicles (ESV) Conference (2003).

[40] Guillemot H., Besnault B., Robin, S., et al., "Pelvic Injuries In Side Impact Collisions: A Field Accident Analysis And Dynamic Tests On Isolated Pelvic Bones," Proceedings of the 16th ESV Conference, Windsor,(1998).

[41] Most recently, Bouquet, et. al. (1998) performed cadaver pendulum impact tests and showed that the pubic symphysis load cell in the EuroSID-1 dummy was a good predictor of pelvic fracture. See Bouquet, R, Ramet, M, Bermond, F, Caire, Y, Talantikite, Y, Robin, S, Voiglio, E, "Pelvis Human Response to Lateral Impact," Proceedings of the 16th Enhanced Safety of Vehicles (ESV) Conference (1998).

[42] A copy of the film is available from the FHWA/NHTSA National Crash Analysis Center Film Library, 20101 Academic Way, Suite 203, Ashburn, VA 20147-2604. Telephone: 703-726-8236; Fax: 703-726-8358.

[43] The 15 percent increase in kinetic energy was computed by taking the difference in kinetic energy (1/2 mass*velocity2) for both velocities of 18 mph and 19.3 mph for a given vehicle and dividing it by the baseline kinetic energy at 18 mph. Since the mass of the vehicle is constant in this example, the percent increase in kinetic energy was approximated by the difference between (20 mph) 2 and (18 mph)2 divided by (18 mph)2.

[44] "Development of a New Biofidelity Ranking System for Anthropomorphic Test Devices" (Stapp Car Crash Journal, Vol. 46, November 2002, pp. 477-512).

[45] Another advantage of the ES-2re dummy is that it is equipped with an articulating arm that can be placed at the side of the thorax, where it acts as an interposer between the vehicle interior and the chest. The arm may also be positioned so that it is elevated, simulating the driving position for the driver, leaving the thorax exposed to direct contact by the vehicle door. The test procedures for the proposed oblique pole test specify elevating the arms of the dummy in the driver’s seat, simulating the driving position. In contrast, the SID-H3 dummy’s arm is built into the torso jacket and can only simulate the condition where the arm is down. Thus, to the extent that the ES-2re dummy’s arm can be positioned in more than one way, that dummy is better able to simulate the results of a variety of side impact crashes.

[46] IIHS began using the SID-IIs in June 2003 in a side impact consumer information program rating the performance of vehicles in tests with a moving deformable barrier. Measures are recorded from the dummy’s head, neck, chest, abdomen, pelvis and leg.

[47] The bony protrusion at the top of the femoral shaft opposite the ball of the hip joint.

[48] IIHS used the same assumption when developing performance standards for its consumer ratings program. See Arbalaez, R. A., et al., "Comparison of the EuroSID-2 and SID-IIs in Vehicle Side Impact Tests with the IIHS Barrier," 46th Stapp Car Crash Journal (2002).

[49] In the IIHS side impact consumer ratings program, 5,100 N is the injury parameter cutoff value for the "Good-Acceptable" range for the combined acetabulum and ilium force values. http://www.highwaysafety.org/vehicle_ratings/measures_side.pdf

[50] The test data also show that the vehicles exceeded or came close to exceeding the 42 mm (1.65 inch) limit specified by the European Union, EU 96/27/EC.

TABLE of CONTENTS