NHTSA Side Crash Protection Research Plan
R&D COURSE OF ACTION
The primary goal of this research plan is improving side crash safety for the U.S. fleet under crash conditions experienced by vehicles in the U.S. fleet, with worldwide harmonization of applicable standards to the extent possible as an important objective. It is imperative that NHTSA undertake the necessary research to ensure that a robust standard based on scientific data evolves to improve side crash safety. Parallel research paths are proposed, with the goals of a near term upgrade of FMVSS 214 and longer term worldwide research to support a harmonized upgraded side impact standard. The parallel paths would have overlapping research tasks, the basis of which would be the identification of the current and projected side impact safety problem in the U.S. side crash environment. The longer term research path will involve development of the necessary scientific bases in terms of test procedures and injury criteria through the IHRA forum, with emphasis on reaching world wide consensus on the test conditions and procedures for improving side impact safety. The path would involve coordination of research with the world wide community, to the extent possible, and generating the research needed to support any short term rulemaking efforts. Such a parallel approach would comply with the Congressional directive to explore harmonization of the side impact standard, while leading to an improved level of side impact safety in the U.S. fleet.
Near Term R&D Goals
Near term research projects are planned with the following goals:
Goal A) to study the benefits, out-of-position (OOP) risks, and costs of the quickly emerging and varied side air bag countermeasure systems.
Goal B) to explore the viability of a fixed up Eurosid-1 as an interim harmonized dummy to promote short term harmonization with the Canadians, vis-a-vis a common North American side impact standard in the near term.
Goal C) to gain an in-depth understanding of the current and projected U.S. side crash environment, including the effects of the changing fleet composition and the representativeness of the striking Moving Deformable Barrier (MDB).
Near Term R&D Projects
To support the near term goals, research projects in three main areas are listed below and graphical represented in Figure A1.
A. Side Impact Air Bags Studies
B. Interim Side Impact Dummy and Injury Criteria Studies
C. Side Impacts Problem Definition
A. Side Impact Air Bags Studies
Several thoracic and head protection side impact air bag systems (SIAB) are emerging in the U.S. market and are projected to become prevalent in the fleet. These inflatable side countermeasures vary widely in designs, sizes, mounting locations and methods, inflation systems, and areas of coverage. In particular, there are several seat and door mounted thorax air bag systems; various versions of window curtain type head protection air bag systems, an inflatable tubular structure head protection system, a combination head/thorax seat mounted air bag system, head protection headrest mounted air bag, etc. Since these system have been demonstrated to have superior protection potential in side crashes, the opportunity to upgrade FMVSS 214 appears to depend on these countermeasures. It is imperative to thoroughly assess performance of these systems and their costs. Specifically, the agency should conduct a critical evaluation of any possible harmful effects for in-position and OOP occupants.
A1. Side Air Bag Data Collection - This task involves the collection of the following three types of data relative to side air bag systems.
1) technical data on the type, design, size and inflation characteristics, sensor type, etc. for the different production and near production side air bag systems
2) data on current and projected penetration into the fleet
3) cost studies
A2. Side Air Bag OOP Studies- This task involves testing side impact air bag systems to determine their threat to out-of-position children and adults. The research will assess the need for incorporating an OOP test requirement in FMVSS 214. It will also assess the need for OOP sensors and/or automatic cut-off switches for these systems. The main concerns are risks of head and neck injury to children, e.g. sleeping child, and risk of arm injury to adults. Appropriate injury criteria and risk data need to be developed (See B. Injury Criteria and Interim Side Impact Dummy Studies.)
A3. Side Air bag Special Crash Investigations - The NHTSA Special Crash Investigations (SCI) program is performing special investigations on side crashes which involved vehicles equipped with side air bags. To date, a total of 26 cases have been initiated. The primary notification sources for special investigations are the NASS, FARS, and the law enforcement community, although the SCI team can be notified of pertinent cases from any source. The data base of cases investigated is expected to grow rapidly as more and more side air bag equipped vehicles are introduced in the U.S. fleet and they become involved in crashes. This data base will provide invaluable field data and insights on the performance and any possible harmful effects of these inflatable side protection systems.
B. Injury Criteria and Interim Side Impact Dummy Studies
Injury Assessment in Dummies - While the FMVSS 214 SID dummy was designed to measure only the acceleration of two ribs, spine and pelvis to compute thoracic and pelvic injury criteria, the Eurosid-1 has additional measurement capabilities, including force and displacement as well as acceleration-based readings. The Eurosid-1 is capable of measuring head acceleration, three rib deflections, three rib accelerations, abdominal forces, pubic symphysis force, shoulder loads, lumbar spine loads, and neck loads.
The agency encountered mechanical deficiencies in the Eurosid-1 dummy, based on a series of eight full scale tests conducted according to the EU 96/27/EC directive. Recently, new rib modules have become available for the Eurosid-1. Preliminary evaluation by NHTSA has indicated that these show promise in addressing one of the main deficiencies in the dummy, the "flat-top" responses in rib deflections. In addition, the shoulder design of the Eurosid-1 can only rotate forward in the horizontal plane. As such, it is very sensitive to impact direction and in the case of an impact slightly forward of pure lateral direction, the shoulder tends to not move at all. Most importantly, however, the Eurosid-1 shoulder cannot displace laterally without rotating. It is desirable for the shoulder be able to displace laterally toward the spine, rotate forward, and shrug up and down vertically. Other issues with the Eurosid-1 include a projecting back plate, bending of the plastic ilium of the pelvis, biofidelity of the abdomen, and upper femur contact with the pubic load cell hardware. The Eurosid-2, as proposed by the EEVC, would potentially address most of the above deficiencies. The following tasks will provide the necessary research for a complete evaluation of the Eurosid-2:
B1. Eurosid-1 Updates Evaluation - Evaluate the Eurosid- 2 in component and sled test conditions (padded, rigid wall, pelvic offset). The testing will evaluate the thoracic responses, investigate the role of the shoulder, and address overall biofidelity of the dummy. Also, evaluate the Eurosid-2 in a limited series of full scale tests in which "flat-top" responses were seen previously to assess if the upgraded dummy eliminates this anomalous behavior.
B2. Evaluate Eurosid-2 in FMVSS 214 - Perform a series of full scale tests as needed.
B3. Evaluate Eurosid-2 in the FMVSS 201 Optional Pole Test - Perform a series of full scale tests as needed.
B4. Eurosid-2 Injury Risk Curves Development - Develop injury risk curves for the body regions whose responses are measured by the Eurosid-2 based on most up to date cadaver test data.
B5. Biofidelity Requirements - Develop the biofidelity requirements for advanced side impact dummies based on the most current cadaver test data.
B5.1. Thoracic and Pelvic Side Injury Criteria Update - Since 1992, NHTSA has been conducting side impact cadaver sled tests with advanced instrumentation to better characterize the human thoracic and pelvic response to lateral impact. Currently, a database of 40 of these sled tests exists in 6 different impact conditions, which will be used to develop injury criteria and dummy requirements. At a minimum, the current thoracic and pelvic injury criteria will be revisited, and, if necessary, updated to reflect the latest research data
B5.2. Abdominal Injury Criteria Development: Using the most up-to-date cadaver testing, establish an abdominal injury criteria for side impact trauma.
B5.3. Head and Neck Side Injury Criteria Development - For both SIAB OOP and effectiveness studies, research is needed to develop injury criteria and injury assessment reference values for the neck and head side trauma for both children and adults, in particular to address the twisting of the neck about the vertical axis. In particular, lateral head injury assessment reference values and the validity of HIC in side crashes need to be fully established.
C. Side Impacts Problem Definition
C1. Crash Data Analyses- NHTSA has initiated a NASS/CDS and FARS study to characterize the current and future side crash environment in the U. S. fleet as part of the definition of the side impact safety problem. The study addresses and evaluates the vehicle involvement, occupant exposure, and incidence of casualties in side impacts with special emphasis on determining the mechanisms of injury. Specific goals consist of performing needed analyses to aid in establishing a test procedure for upgraded side impact protection and to aid in determining the requirements for an advanced side impact dummy. In addition to harmonization and dummy issues, results from the real world crash data, will provide the basis for considering several near term side impact upgrade options.
C2. Fleet Characterization- The growing population of LTVs, as collision partners, is accounting for an increasing percentage of injuries and fatalities in side struck vehicles. The dynamic test procedure in a side impact regulation in the U.S. should address the injury mechanisms that are seen in the current traffic environment as well as provide for improved safety in the projected U.S. side crash environment. The current MDB weight, stiffness, and geometric characteristics need to be evaluated in light of the current and projected safety problems. Through a joint effort of the Side Impact research program and the Vehicle Compatibility and Aggressivity research program, the following tasks will be undertaken to characterize vehicles in side crashes.
C2.1 Fleet Trends - Perform a study to determine fleet makeup and projected growth.
C2.2 Vehicle Stiffness - Based on NCAP load cell barrier data and limited lower speed LTV to load cell fixed barrier testing, determine the stiffness signature of a representative side impact striking vehicle.
C2.3 Vehicle Geometry - Perform field measurement studies to characterize the geometry of a representative side impact bullet .
C2.4 Develop Representative Bullet - If tasks C2.1, C2.3, indicate the need to update the current MDB, then develop an upgraded MDB based on the results from the previous tasks.
C3. Side Air Bag and Advanced Countermeasures Effectiveness Studies - SIABS have been demonstrated to have superior protection potential in side crashes, and thus, the opportunity to upgrade FMVSS 214 appears to depend on these countermeasures. Specifically, head protection SIABS have been shown to have tremendous benefits potential in tree/pole impacts and are believed to have benefits potential when struck by higher vehicles. In addition these systems have been integrated with advanced structural changes and other countermeasures in certain vehicles in the fleet. The following testing will provide data to quantify the effectiveness of SIABS and other advanced side impact countermeasure systems.
C3.1 Effectiveness of advanced systems relative to FMVSS 214 - To investigate overall SIAB effectiveness from the fleet perspective, perform an analysis of FMVSS 214 and side NCAP tests of air bag equipped vehicles. Conduct supplementary 214 tests as needed.
C3.2 Effectiveness of advanced system in impacts with LTVs and poles/trees, and rollovers - To investigate benefits of countermeasures driven by pole test option in FMVSS 2 01, perform a series of full scale tests to assess compliant vehicle performance in more representative and higher severity side crash environment. Use representative MDB for cost effective testing based on results from C2. Fleet Characterization research above. The dummy will be either the SID/HIII or the Eurosid-2, based on results from the B. Interim Side Impact and Dummy Injury Criteria Studies research. The testing will include the following:
o LTV Testing - Perform full scale tests of LTV-to-light vehicle impacts, using baseline and advanced countermeasure vehicles, to assess if a pole test would drive countermeasures that address injuries similar to those induced by aggressive bullets, including LTVs. Dynamic systems such as the Inflatable Curtain (e.g. Volvo, Mercedes), Head Protection System (e.g. BMW), and a combination head/thorax bag (e.g. Ford) will be tested.
o Ejection Mitigation - Perform rollover tests using vehicles with the above three dynamic systems countermeasures installed to assess their ejection mitigation potential.
The research in the proposed projects will aid the agency in making decisions with regards to short term harmonization and short term upgrades for FMVSS 214. Also, it is evident that these projects are part of, overlap with, or feed into the overall long term research tasks outlined in the following section.
NEAR TERM AGENCY DECISION POINTS
With results from the ongoing research described above, several agency decision points are anticipated, in a two to three year time frame, for future courses of action to improve side crash protection:
I. OOP test requirements with child and possibly 5th female dummies in FMVSS 214.
II. Incorporate Eurosid-2 into FMVSS 214 .
III. Upgrade the 214 MDB to be more representative of current and future striking vehicles and adopt the Eurosid-2 if appropriate, or otherwise the SID/HIII.
IV. Incorporate supplementary pole test in FMVSS No. 214 with the Eurosid-2 or SID/HIII dummy.
Long Term R&D and Coordination through IHRA
It is imperative that NHTSA undertake the necessary research to ensure that a long term robust standard based on scientific data evolves to improve side crash safety. The following research will implement the necessary technical steps to achieve this goal. To the extent possible NHTSA will coordinate with the IHRA Biomechanics and Side Impact Working Groups to foster international harmonization. Participation in the long term research effort by other governments, industry counterparts, and other partners early in the process will shorten the time spent on industry-government dialogues in reaching a consensus for improving side impact safety. The tasks which make up the agency's long term side impact research are listed below and are incorporated into Figure A1:
Task 1 - Real World Studies: Determine the latest definition of the side impact safety problem and determine the opportunities for enhancing occupant side impact protection.
Task 2 - Dummy Performance Criteria: Based upon the results of Task 1, establish priority-ranked mechanical performance requirements for a side impact dummy.
Task 3 - Evaluation and/or Development of Injury Criteria: Review and evaluate injury data to identify the most meaningful injury criteria in terms of reduction of human injury risk in side crashes. Develop additional criteria to reflect the findings of Task1, as necessary.
Task 4 - Evaluation of Existing Dummies: Evaluate the response of existing dummies based upon performance criteria developed in Task 2.
Task 5 - Design, Develop, Test & Evaluate Needed Dummy Modifications: Based upon the results of task 4, modify the most suitable dummy to meet the performance requirements of tasks 2 and 3. Eventual outcome of this process should be a single dummy or family of dummies.
Task 6 - Test Procedures Development: Develop or modify the test devices and test procedure(s) to reflect the findings of Task 1, as necessary.
Task 7 - Vehicle Fleet Baseline Performance: Determine the safety performance of the vehicle fleets to the test procedure developed.
Task 8 - Countermeasures Development & Evaluation: Develop/Evaluate vehicle countermeasures to protect occupants in the proposed test procedure(s).
During and upon the completion of each task, the data and findings will be shared with the IHRA working groups. The emphasis will be on reaching world wide consensus on an advanced side impact dummy and corresponding injury criteria and, to the extent possible, achieving commonalities in the area of side impact test procedure. The underlying goal for NHTSA's R&D is to improve side impact safety, and it is anticipated that the research outlined above will be undertaken within the framework of the IHRA working groups. However, it may be necessary for the agency to work independently to achieve its goals in a timely manner. Many of the agency's near term activities will contribute to these long term goals that are within the framework of the IHRA working group.