NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: aiam1167OpenMr. Ken Watts, Baruch Manufacturing Co., Box 385, Linden, New Jersey 07038; Mr. Ken Watts Baruch Manufacturing Co. Box 385 Linden New Jersey 07038; Dear Mr. Watts: This is in response to your request of June 9, 1973, for informatio concerning Standard 125, Warning devices. You inquire about the sale and use of non-conforming devices manufactured both before and after January 1, 1973, the preemption effect of this standard on State laws, use of an NHTSA recommendation in promotional literature, and the availability and content of Docket 4-2.; The Vehicle Safety Act prohibits the manufacture of non-conformin devices on or after the effective date of Standard 125. This means a device manufactured before the effective date of January 1, 1974, may still be legally offered for sale after that date. Any non-conforming devices manufactured after January 1, 1974, would be subject to a penalty of up to $1,000 per device. In addition, the NHTSA could (1) seek an injunction to restrain further manufacture and sale, (2) order defect notification, and (3) recommend a recall campaign of those devices already sold.; The NHTSA takes no position on the issue of product liability i private litigation stemming from the use of 'old style' devices or conforming devices, and the NHTSA is not in a position to indicate to you the point of view of private insurance companies.; This standard preempts State law by establishing one set o requirements for warning devices without a self-contained energy source, and prohibiting any State standard that is not identical to the Federal one. It is unlikely that these devices could be prohibited in local use because no alternative can be legally manufactured after January 1, 1974.; The NHTSA does not recommend any particular product subject to th motor vehicle safety standard. To state or imply NHTSA approval of a particular device or recommendation of its use as motor vehicle standard equipment would be a misrepresentation. Each manufacturer must mark a warning device with the DOT symbol or the statement that the device complies with all applicable Federal motor vehicle safety standards (S5.1.4(c)).; Docket 4-2 is open to public inspection without any notice o application requirements between 8:00 a.m. and 5:00 p.m. (4:15 p.m. from now until July 9, 1973). It does not contain comprehensive material on State regulations. The Highway Users Federation for Safety and Mobility, 1776 Massachusetts Avenue, N.W., Washington, D.C. 20036, should be able to supply you with this information. Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: nht90-1.24OpenTYPE: INTERPRETATION-NHTSA DATE: 01/26/90 FROM: Stephen P. Wood -- NHTSA Acting Chief Counsel TO: John G. Sims -- Governmental Affairs Champion Motor Coach, Inc. TITLE: NONE ATTACHMT: LETTER FROM JOHN, G. SIMS -- CHAMPION MOTOR COACH INC. DATED 11/06/89 TO ROBERT F. HELLMUTH -- NHTSA; RE FMVSS 217; REFERENCE NO NEF-31 RSH; CIR 2996 TEXT: Dear Mr. Simms: This responds to your November 6, 1989 letter to Robert Hellmuth, Director of NHTSA's Office of Vehicle Safety Compliance (OVSC). In that letter, you stated that OVSC had misinterpreted and misapplied the requirements of S5.5.1 and S5.5.2 of Standard No . 217, Bus Window Retention and Release (49 CFR @ 571.217). I conclude that OVSC correctly interpreted those sections of Standard No. 217 and correctly applied those sections to your company's buses. The buses in question are not school buses and have a gross vehicle weight rating of more than 10,000 pounds. For such buses, section S5.5.1 of Standard No. 217 provides that: " . . . each emergency door shall have the designation 'Emergency Door' or 'E mergency Exit' . . . followed by concise operating instructions describing each motion necessary to unlatch and open the exit, located within 6 inches of the release mechanism." Your company has designated the door immediately adjacent to the driver's seating position in these buses as an emergency exit. Operating instructions for that emergency exit are located within 6 inches of the release mechanism. However, the designation of this door as an emergency exit appears on a label located on a stanchion immediately behind the driver's seat, facing the passenger seating area. This designation does not appear within 6 inches of the release mechanism. You suggest that this arran gement complies with Standard No. 217, because S5.5.1 requires only the operating instructions, and not the emergency exit designation, to be located within 6 inches of the release mechanism. I disagree with your suggestion. While it might be possible to construe the language of S5.5.1 in the manner you suggest, the agency has consistently interpreted S5.5.1 as requiring that both the emergency exit designation and the operating instructions be located within 6 inches of the release mechanism. Nothing in the correspondence you refer to undermines this conclusion. 2 Contrary to the assertion in your letter, there is a clear safety basis for requiring the emergency exit designation to be within 6 inches of the emergency exit release mechanism. This ensures that any person reaching the exit can quickly find both the release mechanism and the instructions. In an emergency, persons are used to finding an emergency exit where they see a label with the designation "Emergency Exit." In your company's buses, a person seeing the emergency exit label located on the driver' s seat stanchion could be misled into thinking that there is an exit somewhere behind the driver's seat, rather than at the driver's door, thus wasting valuable escape time. This is exactly the type of situation S5.5.1 is intended to prevent. Your letter also suggests that requiring the emergency exit designation within 6 inches of the release mechanism would substantially reduce the visibility of the emergency exit sign, since the operating mechanism is frequently located below the shoulder level of seated passengers. While this may be true in some cases, I do not believe it would be likely to impede emergency egress. In an emergency situation, the occupants of the seat adjacent to the exit are likely to be the first ones out of the exit, and would thus no longer impede the visibility of the exit designation for other passengers seeking to exit. We are only focusing on the designation here. Also, once it is open, the instructions aren't needed. Your letter also suggests that the emergency exit requirements for school buses, contained in S5.5.3, support your interpretation of S5.5.1, because the school bus emergency exit requirements specifically authorize the separation of the emergency exit de signation and operating instructions. I must again disagree with you on this point. NHTSA recognized the considerable differences between school buses and other buses when Standard No. 217 was being developed. S5.5.3 addresses a very different set of circumstances. School buses typically have one emergency door, located at or near the rear of the bus. The requirement in S5.5.3 that the designation be in letters at least two inches high "at the top of or directly above the emergency exit" is designe d to ensure that school bus passengers will be able to locate this exit from any seating position in the bus. This is not the case for your company's buses, which feature several window exits located throughout the bus, in addition to the exit at issue here. The second issue raised in your letter concerns the requirements of S5.5.2 of Standard No. 217. That section requires that emergency exit "markings" be visible to occupants in specified locations, under lighting and occupant visual acuity conditions set forth in S5.5.2. You suggested that the emergency exit "markings" referenced in S5.5.2 refers only to the designation of an exit as an emergency exit, and not to the operating instructions for that emergency exit. I disagree with this suggestion as wel l. 3 As we noted earlier, S5.5.1 sets forth requirements for both emergency exit designations and emergency exit operating instructions. Immediately following these requirements, S5.5.2 specifies that "each marking shall be legible . . ." (emphasis added). S5.5.2 nowhere draws any distinction between markings designating an exit as an emergency exit and markings setting forth operating instructions for the emergency exit. Neither is any such distinction inherent in the use of the term "marking." According ly, the ordinary meaning of the term "marking" and the background of this regulatory provision show that as used in S5.5.2, the word "markings" refers to both the emergency exit designation and the emergency exit operating instructions required by S5.5.1 . If you have any further questions concerning these issues, please feel free to contact David Greenburg of this office at (202) 366-2992. Sincerely, |
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ID: 2281yOpen Mr. John G. Sims Dear Mr. Sims: This responds to your November 6, 1989 letter to Robert Hellmuth, Director of NHTSA's Office of Vehicle Safety Compliance (OVSC). In that letter, you stated that OVSC had misinterpreted and misapplied the requirements of S5.5.1 and S5.5.2 of Standard No. 217, Bus Window Retention and Release (49 CFR 571.217). I conclude that OVSC correctly interpreted those sections of Standard No. 217 and correctly applied those sections to your company's buses. The buses in question are not school buses and have a gross vehicle weight rating of more than 10,000 pounds. For such buses, section S5.5.1 of Standard No. 217 provides that: "... each emergency door shall have the designation 'Emergency Door' or 'Emergency Exit' ... followed by concise operating instructions describing each motion necessary to unlatch and open the exit, located within 6 inches of the release mechanism." Your company has designated the door immediately adjacent to the driver's seating position in these buses as an emergency exit. Operating instructions for that emergency exit are located within 6 inches of the release mechanism. However, the designation of this door as an emergency exit appears on a label located on a stanchion immediately behind the driver's seat, facing the passenger seating area. This designation does not appear within 6 inches of the release mechanism. You suggest that this arrangement complies with Standard No. 217, because S5.5.1 requires only the operating instructions, and not the emergency exit designation, to be located within 6 inches of the release mechanism. I disagree with your suggestion. While it might be possible to construe the language of S5.5.1 in the manner you suggest, the agency has consistently interpreted S5.5.1 as requiring that both the emergency exit designation and the operating instructions be located within 6 inches of the release mechanism. Nothing in the correspondence you refer to undermines this conclusion. Contrary to the assertion in your letter, there is a clear safety basis for requiring the emergency exit designation to be within 6 inches of the emergency exit release mechanism. This ensures that any person reaching the exit can quickly find both the release mechanism and the instructions. In an emergency, persons are used to finding an emergency exit where they see a label with the designation "Emergency Exit." In your company's buses, a person seeing the emergency exit label located on the driver's seat stanchion could be misled into thinking that there is an exit somewhere behind the driver's seat, rather than at the driver's door, thus wasting valuable escape time. This is exactly the type of situation S5.5.1 is intended to prevent. Your letter also suggests that requiring the emergency exit designation within 6 inches of the release mechanism would substantially reduce the visibility of the emergency exit sign, since the operating mechanism is frequently located below the shoulder level of seated passengers. While this may be true in some cases, I do not believe it would be likely to impede emergency egress. In an emergency situation, the occupants of the seat adjacent to the exit are likely to be the first ones out of the exit, and would thus no longer impede the visibility of the exit designation for other passengers seeking to exit. We are only focusing on the designation here. Also, once it is open, the instructions aren't needed. Your letter also suggests that the emergency exit requirements for school buses, contained in S5.5.3, support your interpretation of S5.5.1, because the school bus emergency exit requirements specifically authorize the separation of the emergency exit designation and operating instructions. I must again disagree with you on this point. NHTSA recognized the considerable differences between school buses and other buses when Standard No. 217 was being developed. S5.5.3 addresses a very different set of circumstances. School buses typically have one emergency door, located at or near the rear of the bus. The requirement in S5.5.3 that the designation be in letters at least two inches high "at the top of or directly above the emergency exit" is designed to ensure that school bus passengers will be able to locate this exit from any seating position in the bus. This is not the case for your company's buses, which feature several window exits located throughout the bus, in addition to the exit at issue here. The second issue raised in your letter concerns the requirements of S5.5.2 of Standard No. 217. That section requires that emergency exit "markings" be visible to occupants in specified locations, under lighting and occupant visual acuity conditions set forth in S5.5.2. You suggested that the emergency exit "markings" referenced in S5.5.2 refers only to the designation of an exit as an emergency exit, and not to the operating instructions for that emergency exit. I disagree with this suggestion as well. As we noted earlier, S5.5.1 sets forth requirements for both emergency exit designations and emergency exit operating instructions. Immediately following these requirements, S5.5.2 specifies that "each marking shall be legible ..." (emphasis added). S5.5.2 nowhere draws any distinction between markings designating an exit as an emergency exit and markings setting forth operating instructions for the emergency exit. Neither is any such distinction inherent in the use of the term "marking." Accordingly, the ordinary meaning of the term "marking" and the background of this regulatory provision show that as used in S5.5.2, the word "markings" refers to both the emergency exit designation and the emergency exit operating instructions required by S5.5.1. If you have any further questions concerning these issues, please feel free to contact David Greenburg of this office at (202) 366-2992. Sincerely,
Stephen P. Wood Acting Chief Counsel ref:217 d:l/26/90 |
1970 |
ID: aiam5350OpenMr. Michael E. Klima Managing Engineer Failure Analysis Associates, Inc. 2100 East Maple Road, Suite 200 Birmingham, MI 48009; Mr. Michael E. Klima Managing Engineer Failure Analysis Associates Inc. 2100 East Maple Road Suite 200 Birmingham MI 48009; Dear Mr. Klima: This responds to your letter of March 29, 1994, to Mr Edward Jettner of this agency concerning the dynamic testing requirements of Standard No. 208, Occupant Crash Protection. Your questions concern the application of this standard to a pickup truck manufactured in April 1988 with a gross vehicle weight rating (GVWR) of 4,400 pounds. You asked whether the injury criteria in S6 apply to this truck, whether a 35 mph fixed barrier crash test is required, and which sections of Standard No. 208 apply to this truck. The safety belt installation requirements for all vehicle types are set forth in Standard No. 208. Section S4.2.1 of Standard No. 208 gives vehicle manufacturers a choice of three options for providing occupant crash protection in trucks and multipurpose passenger vehicles with a GVWR of 10,000 pounds or less, manufactured on or after January 1, 1976 and before September 1, 1991. Option 1, set forth in S4.1.2.1, requires vehicle manufacturers to provide automatic protection at the front outboard seating positions, and either meet the lateral crash protection and rollover requirements by means of automatic protection systems or have manual safety belts at the front outboard seating positions such that those positions comply with the occupant protection requirements when occupants are protected by both the safety belts and the automatic protection. Option 2, set forth in S4.1.2.2, requires vehicle manufacturers to provide a lap or lap/shoulder safety belt at every seating position, have automatic protection for the front outboard seats, and have a warning system for the safety belts provided. Option 3, set forth in S4.1.2.3, requires the manufacturer to install lap or lap/shoulder safety belts at every seating position and to have a warning system for those belts. According to your letter, the manufacturer installed Type 2 seat belt assemblies at the front outboard seating positions. This suggests that the manufacturer chose to comply with Option 3. Under this option, the only requirements in Standard No. 208 that those belts were required to comply with were S7.1, S7.2, and S7.3. The belts were also required to comply with the requirements of Standard No. 209, Seat Belt Assemblies. The manufacturer was not required to certify that the vehicle complied with the dynamic testing requirements of Standard No. 208. The injury criteria in S6 of the standard are applicable only to vehicles which must comply with the dynamic testing requirements. Standard No. 208 does not include a 35 mph fixed barrier crash test requirement. The dynamic crash test in Standard No. 208 is barrier crash test at any speed up to 30 mph. NHTSA does perform some 35 mph barrier crash tests as part of the New Car Assessment Program (NCAP). NCAP is a consumer information program, not a safety compliance test. NHTSA does not test every vehicle under this program. In the 1993 model year program, NHTSA tested 37 new vehicles and released results on 68 additional vehicles which had been tested previously and had not changed significantly in model year 1993. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: nht76-2.18OpenDATE: 11/15/76 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Gillig Bros. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of September 13, 1976, in which you ask whether Standard No. 222, School Bus Passenger Seating and Crash Protection, requires that the 20-inch maximum separation between the seating reference point and the rear surface of the restraining barrier be measured at the point of greatest distance between the two. The restraining barrier you describe has padded tubing around its circumference which would be closer to the seating reference point than the center section of the barrier. The National Highway Traffic Safety Administration (NHTSA) interprets the requirements of paragraph S5.2.1 of Standard No. 222 to mean that the 20-inch distance must be measured from the seating reference point to the surface of the seat back or restraining barrier, exclusive of portions which protrude from the basic contour of the surface. The side tube portion would constitute such a protrusion. SINCERELY, September 13, 1976 Thomas W. Herlihy Office of Chief Counsel National Highway Traffic Safety Administration We have a question relative to School Bus Safety Standard Number 222. The standard states "that there shall not be more than 20" from the seating reference point to the rear surface of the restraining barrier". This distance being measured along a horizontal longitudinal line through the S.R.P in the forward direction. Our question is this: What is considered the rear surface. Is it part furthest to the rear, which in our case would be the padding on the side tube portion of our seat frame? Or is it considered to be the rear padding on the sheet metal center section of the seat? Attached is a sketch which we hope will clarify our question. As our new seat spacing design requirements hinge on your answer, we would appreciate your written answer as early as possible. Lewis C. Coffey Chief Engineer cc: TIMOTHY HOYT -- OFC. OF CRASHWORTHINESS (Graphics omitted) (Graphics omitted) |
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ID: aiam5454OpenMr. Rishi Gupta Autolite (India) Limited D-483 Road No. 9-A Vishwalkarma Industrial Area Jaipur 302 013 India; Mr. Rishi Gupta Autolite (India) Limited D-483 Road No. 9-A Vishwalkarma Industrial Area Jaipur 302 013 India; Dear Mr. Gupta: This is in reply to your FAX of August 29, 1994, t Richard Van Iderstine of this agency. For future reference, requests for interpretations of U.S. Federal motor vehicle safety regulations should be addressed to the Office of Chief Counsel. You have asked whether the size and types of aiming pads you propose to place on headlamps manufactured by Autolite conform to DOT specifications. You describe these headlamps as 'a 7' round and a 200 x 142 mm rectangular replaceable halogen sealed beams which use a replaceable halogen bulb (HB2).' You enclosed diagrams showing 'aiming pad's position as per SAE J1383 - 1992' (Figures 1 and 3), and in the manner you wish to place them on the Autolite lamps (Figures 2 and 4). We understand that these replaceable bulb headlamps are intended to be sold as replacements for sealed beam headlamps of the same dimensions. Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices, and Associated Equipment, is the DOT specification that applies to Autolite's headlamps. The aimability performance requirements for non-sealed beam headlamps are found in S7.8. of Standard No. 108. S7.8 allows any aiming pad pattern that will fit on the headlamp and that will allow any one of the available aiming adapters described in SAE J602 to be used on the headlamp. Specifically, S7.8.1 in pertinent part allows non-sealed beam headlamps to be equipped with aiming pads to be used with the photometric procedures of SAE J1383 APR85 (not '1992' as you wrote) when being tested for photometric compliance, and to serve for the aiming reference when the lamp is installed on a motor vehicle. S7.8.5 allows an installed headlamp system to be aimable with an externally applied aiming device. Under S7.8.5.1, this aiming device shall be the equipment specified in SAE Standard J602 OCT80 Headlamp Aiming Device for Mechanically Aimable Sealed Beam Headlamp Units. You write that the aiming pad sizes and types you wish to use are identical to those on headlamps sold by Hella, and that ETL Testing Laboratories has told you that the aiming pad positions and types meet DOT specifications. This indicates that Autolite's headlamps would be mechanically aimable with SAE J602 equipment, and therefore permissible as meeting Standard No. 108. We recommend that Autolite verify mechanical aimability with SAE J602 equipment before certifying compliance with Standard No. 108. Our engineering staff has reviewed your letter and asks that we point out the following errors in Autolite's Figures Nos. 2 and 4. Under both Figures, there is a reference to 'HB-2 (H4 P43t).' The HB2 light source is not the same as the H4 P43t light source. The HB2 is a light source permitted by Standard No. 108 while the H4 P43t is not permitted by the Standard for motor vehicles. Under the drawing, the dimension '68.5' should be '68.58 +/- 0.51' (see Figure 4-4 of Standard No. 108). The dimensions of '32' and '52.0' must be the sum of two dimension 'A's from Figure 4-4, thus the sum is 42.16 +/- 0.25 + 42.16 +/- 0.25 = 84.32 +/- 0.50, not 84 as nominally calculated. Finally, with respect to Figure 4 only, because this lamp is intended to replace a 200 x 142 mm sealed beam lamp, the position of the aiming pads are not, but should be identical to the 200 x 142 mm sealed beam to facilitate mechanical aim when only one headlamp is replaced. Sincerely, Philip R. Recht Chief Counsel; |
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ID: 1983-3.3OpenTYPE: INTERPRETATION-NHTSA DATE: 09/06/83 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: BMW of North America, Inc. TITLE: FMVSS INTERPRETATION TEXT:
September 6, 1983 NOA-30
Mr. Karl-Heinz Ziwica, Manager Safety & Emission Control Engineering BMW of North America, Inc. Montvale, New Jersey 07645
Dear Mr. Ziwica:
This responds to your letter requesting an interpretation of Standard No. 105, Hydraulic Brake Systems. Your request was in regard to a type of brake reservoir you are considering producing which would contain common fluid for the brake circuits and the brake hydraulic power assist unit. The issue raised by your letter was whether section S5.4.2 of the stnadard permits the common fluid to be counted as part of the minimum capacity required for the braking system. As discussed below, the answer to that question is no.
The first sentence of section S5.4.2 states:
Reservoirs, whether for master cylinders or other type systems, shall have a total minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position (as adjusted initially to the manufacturer's recommended setting) to a fully worn, fully applied position, as determined in accordance with S7.18(c) of this standard. As noted by your letter, the agency has previously interpreted this section with respect to a brake reservoir servicing both the braking system and the clutch. In an October 9, 1981, letter to Toyota, we explained:
This section specifies the total minimum fluid capacity that a vehicle's braking system reservoirs must have. That amount is determined by reference to the vehicle's braking system, i.e., by the fluid displacement which results when all the wheel cylinders or caliper pistons serviced bythe reservoirs move from a new lining, fully retracted position to a fully worn, fully applied position. The purpose of this requirement is to assure that a vehicle's braking system reservoirs have adequate fluid capacity to service the brakes.
The agency interprets section S5.4.2 to require that the minimum fluid capacity requirements be met by fluid which is solely available to the brakes. If fluid is available to both the brakes and the clutch, some of that fluid will be used by the clutch in normal service and thus be unavailable to the brakes. In the event of clutch failure, all of the common fluid may be used by the clutch. Therefore, while Standard No. 105 does not prohibit manufacturers from producing master cylinders with reservoirs that have some fluid available to both the braking system and the clutch, none of that common fluid may be counted toward meeting the minimum requirements of section S5.4.2.
This same rationale applies to a reservoir which contains common fluid for the brake circuits and brake hydraulic power assist unit. As indicated in our October 1981 letter, the minimum fluid capacity requirements were determined by reference to the vehicle's braking system for the purpose of assuring that a vehicle's braking system reservoirs have adequate fluid capacity to service the brakes, i.e., the wheel cylinders and pistons. More specifically, the requirement for minimum capacity equivalent to the fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoirs move from a new lining, fully retracted position to a fully worn, fully applied position, was based upon maintaining a sufficient supply of fluid to enable a vehicle to stop even when there was complete brake lining wear-out in the service brakes. Put another way, the requirement assures an adequate supply of brake fluid over the lifetime of the brake linings, even if a driver fails to add fluid as part of routine maintenance.
This purpose would not be met if fluid available to both the brake circuits and brake hydraulic power assist unit was counted toward meeting the minimum fluid capacity requirements. Some of the common fluid would be used by the brake hydraulic power assist unit in normal service and thus be available to the brake circuits. Moreover, in some instances of brake hydraulic power assist unit failure (e.g., a failure in the brake hydraulic power assist unit return line), all of the common fluid might be used by that unit. Sincerely,
Frank Berndt Chief Counsel Enclosure
May 11, 1983
Mr. Frank Berndt Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation 400 Seventh Street S.W. Washington DC 20590 RE: Request for Interpretation - FMVSS 105-75
Dear Mr. Berndt
For future models, BMW is considering a new braking system with hydraulic power assist. Included in this system is a brake fluid reservoir which would contain common fluid for the brake circuits and the brake hydraulic power assist pump. This design is shown in the attached drawing, where X and Y are the individual reservoir compartments for the brake circuits and Z is the compartment for the brake hydraulic power assist pump. The area marked W represents fluid available to both the brake circuits and the brake power assist pump.
We request an interpretation of S 5.4.2 (reservoir capacity) of FMVSS 105-75, with respect to the proposed brake fluid reservoir described above.
We have reviewed the various interpretations given by NHTSA, and are unable to find any opinions which apply to our specific reservoir. Among the interpretations applicable to "multi-purpose" reservoirs is one given to Toyota in a letter from Mr. F. Berndt, dated October 9, 1981. The response to Toyota presented the agency's position that "the minimum fluid capacity requirements for brake reservoirs be met by fluid which is not available to the clutch, either during normal use or in the event of clutch failure".
We believe that the agency's position is appropriate with respect to a common brake/clutch system. A leak in the line to the clutch would not necessarily cause failure of the clutch itself; hence, there would be no warning that a leak existed and that the fluid level in the reservoir was being depleted. Thus, a driver could go through a complete set of brake linings without recognizing the leak. It is therefore brake and clutch systems should not be counted towards meeting the reservoir capacity requirements of S 5.4.2. If, however, a leak should occur in the brake power assist subsystem of BMW's proposed design, the braking power assist ("boost") fails after a few brakings, Because the Boost pump compartment (Z) of the reservoir has been emptied. In this case, the fluid level warning lamp would be activated, due to the fact that the fluid level warning point is located above the walls of the boost compartment. Additionally, the warning lamp provided specifically for power assist unit pressure will be activated. Vehicle braking can be achieved through the application of increased pedal pressures, in compliance with S 5.1.2.1, S 5.1.3.4, S 6.13, and S 7.9 of FMVSS 105-75. Further, the amount of fluid remaining in compartments X and Y of the BMW reservoir is sufficient to meet the requirements of the second sentence of S 5.4.2., which is as follows:
"Reservoirs shall have completely separate compartments for each subsystem except that in reservoir systems utilizing a portion of the reservoir for a common supply to two or more subsystems, individual partial compartments shall each have a minimum volume of fluid equal to at least the volume displaced by the master cylinder piston servicing the subsystem, during a full stroke of the piston." With regard to the total minimum capacity requirements of S 5.4.2 (full lining wear) under the condition of a power assist unit leak, neither the sum of the two brake circuit compartment volumes (X,Y) nor either of them are equivalent to the fluid displacement resulting when all wheel cylinders move from a new lining condition to a fully worn position.
We believe it highly unlikely that, under the conditions just described (lack of power assist, 100 - 150 pound pedal force for deceleration, and activation of two warning lights) a driver would wear down a complete set of brake linings over a typical range of 20,000 to 40,000 miles. In such a case, it would be reasonably expected that a driver would seek repair at a dealer or service station immediately upon loss of brake power assist and long before the brake linings were fully worn.
We respectfully submit, therefore, that the power assist unit should be considered an integral part of the brake system and should be recognized as a subsystem of the brake system for which the same requirements applying to brake subsystem leakage should also be valid. In our view this is a reasonable assumption because, as detailed earlier, the driver will receive immediate warning of a fluid leak, in the form of a loss of brake power assist, as well as activation of two warning lights. Similarly, a loss of fluid from a brake circuit would also be obvious to the driver, since pedal effort would increase noticeably and a warning light would be activated. As a further example, the proposed BMW system would comply with the following sections of FMVSS 105-75, if the power assist unit is considered a subsystem and if a leak developed in that subsystem (compartment Z):
S 5.1.2 Partial Failure S 5.4.1 Master Cylinder Reservoir S 6.13 Control Forces S 7.9 Service Brake System Test Partial Failure
We believe a final point which should be considered by the NHTSA regarding BMW's proposed design is international harmonization. As an exporter of vehicles to a number of markets throughout the world, our goal is to design components (including brake fluid reservoirs) to comply with as many different national regulations as possible. In the case of our proposed reservoir, the U.S. and Japanese requirements conflict with regard to total reservoir capacity. FMVSS 105-75, based on previous NHTSA interpretations, refers to the fluid volume available exclusively to the brake system. On the other hand, Japanese requirements apply to the total reservoir capacity, including every and all subsystems. If the volumes of X and Y were increased to provide sufficient fluid within them to meet the requirements of S 5.4.2., we would be forced, in order to comply with Japanese regulations, to increase the volume W as shown on the attached drawing. The total reservoir capacity, already a significant amount (700 cc), would have to be increased dramatically (43 ?) to approximately one liter in order to meet NHTSA's interpretation of brake/clutch reservoirs. Further, we would be required to raise the position of the switch point for the fluid level warning light. This could result in unnecessary activations of the warning signal. Through normal use, the fluid could drop to a level which would switch-on the warning light, but this level of fluid would still meet S5.4.2 requirements and would not represent a "low" fluid level condition.
Interpretation of the power assist unit as a subsystem of the proposed BMW brake system will allow BMW to market a common reservoir worldwide, rather than being forced to manufacture a unique reservoir exclusively for the U.S. market.
To summarize, the proposed BMW brake fluid reservoir would contain the S 5.4.2 total minimum capacity fluid requirement when the brake power assist unit is considered to be a subsystem of the total brake system. We believe that inclusion of the power assist unit circuit as a brake subsystem is valid for the following reasons. First, in the event of a fluid leak in the power assist unit circuit, the driver would receive multiple warnings (increased pedal effort, warning lights) in a manner analogous to the warnings received when a brake circuit leak occurs. Second, the proposed BMW system, including the power assist unit subsystem would be accurately described by the S 4. definition of "split service brake system", which "...means a brake system consisting of two or more subsystems actuated by a single control designed so that a leakage-type failure of a pressure component in a single subsystem (except structural failure of a housing that is common to two or more subsystems) shall not impair the operation of any other subsystem."
Accordingly, we believe that the proposed BMW brake fluid reservoir described in this letter would fulfill the requirements of S 5.4.2 with regard to total minimum reservoir capacity. We ask that you confirm our interpretation at your earliest convenience. Very truly yours,
Karl-Heinz Ziwica, Manager Safety & Emission Control Engineering
WS/fw 0104 - 83
Encl.
BMW PROPOSED BRAKE FLUID RESERVOIR
***Insert Diagram Below*** |
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ID: 7782Open The Honorable John D. Dingell Dear Chairman Dingell: Thank you for your letter of September 17, 1992, enclosing correspondence from Mr. Aaron Gordon concerning seat belts on school buses. You requested comments on Mr. Gordon's letter and on H.R. 896, a bill referred to in Mr. Gordon's letter. The issue of safety belts on school buses is an important topic which the National Highway Traffic Safety Administration (NHTSA) has thoroughly studied for many years. School bus transportation has been and continues to be one of the safest forms of transportation in America. Every year, approximately 370,000 public school buses travel approximately 3.5 billion miles to transport 22 million children to and from school and school-related activities. Since NHTSA began tracking traffic fatalities in 1975, an average of 16 school bus occupants per year have sustained fatal injuries. While each of these fatalities is tragic, the number of school bus occupant fatalities is small compared to the number of occupant fatalities to children in other types of vehicles. For example, in 1989 there were 5,287 deaths among children aged five to 18 in vehicles other than school buses. In 1977, NHTSA issued Federal motor vehicle safety standard No. 222, School Bus Passenger Seating and Crash Protection, which established minimum crash protection levels for occupants of all school buses. For large school buses, those with a gross vehicle weight rating (GVWR) above 10,000 pounds, the standard requires occupant protection through a concept called "compartmentalization" -- strong, well- padded, well-anchored, high-backed, evenly spaced seats. The effectiveness of "compartmentalization" has been confirmed by independent studies by the National Transportation Safety Board (NTSB) and the National Academy of Sciences (NAS). Under the current requirements of Standard No. 222, small school buses, those with a GVWR of 10,000 pounds or less, must provide "compartmentalization" and be equipped with lap or lap/shoulder belts at all designated passenger seating positions. The agency believes that safety belts are necessary in addition to "compartmentalization" in small school buses because of their smaller size and weight, which are closer to that of passenger cars and light trucks. In 1987, the NTSB completed a study of the crashworthiness of large school buses, and concluded that most school bus occupant fatalities and serious injuries were "attributable to the occupants' seating position being in direct line with the crash forces. It is unlikely that the availability of any type of restraint would have improved their injury outcome." In 1989, NAS completed a study of means to improve school bus safety and concluded that "the overall potential benefits of requiring seat belts on large school buses are insufficient to justify a Federal requirement for mandatory installation. The funds used to purchase and maintain seat belts might better be spent on other school bus safety programs and devices that could save more lives and reduce more injuries." The NAS pointed out that since children are at greater risk of being killed in school bus loading zones (i.e., boarding and leaving the bus) than on board school buses, "a larger share of the school bus safety effort should be directed to improving the safety of bus loading zones." A summary of the NAS report is enclosed. In response to the recommendations from the NAS study, NHTSA has initiated several rulemaking actions, such as improvements to school bus visibility by the driver and requiring stop signal arms on school buses, designed to improve the safety of students in school bus loading zones. Besides the actions taken in response to the NAS study, NHTSA has initiated several other rulemaking activities to improve further the safety of school buses, e.g., increasing the number of emergency exits, establishing wheelchair securement/occupant restraint requirements, and improving the body joint strength requirements. While there are no Federal requirements for safety belts on large school buses, states are free to install them if they feel it is in the best interest in their state. However, as noted in the NAS report, if the safety belts are to be beneficial, "states and local school districts that require seat belts on school buses must ensure not only that all school bus passengers wear the belts, but that they wear them correctly." In summary, the safety record of school buses is outstanding. As such, there is no compelling evidence to suggest that safety belts would provide even higher levels of occupant crash protection. Also, the agency agrees with the conclusion from the NAS report, that there is insufficient reason for a Federal mandate for safety belts on large school buses. I hope you find this information helpful. Sincerely,
Marion C. Blakey Enclosure cc: Mr. Aaron Gordon ref:222 d:11/9/92 |
1992 |
ID: nht92-2.41OpenDATE: 11/09/92 FROM: MARION C. BLAKEY ADMINISTRATOR, NHTSA TO: HONORABLE JOHN D. DINGELL -- CHAIRMAN, COMMITTEE ON ENERGY AND COMMERCE, U.S. HOUSE OF REPRESENTATIVES COPYEE: MR. AARON GORDON ATTACHMT: ATTACHED TO LETTER DATED 9-17-92 FROM JOHN D. DINGELL TO MARION C. BLAKEY TEXT: Thank you for your letter of September 17, 1992, enclosing correspondence from Mr. Aaron Gordon concerning seat belts on school buses. You requested comments on Mr. Gordon's letter and on H.R. 896, a bill referred to in Mr. Gordon's letter. The issue of safety belts on school buses is an important topic which the National Highway Traffic Safety Administration (NHTSA) has thoroughly studied for many years. School bus transportation has been and continues to be one of the safest forms of transportation in America. Every year, approximately 370,000 public school buses travel approximately 3.5 billion miles to transport 22 million children to and from school and school-related activities. Since NHTSA began tracking traffic fatalities in 1975, an average of 16 school bus occupants per year have sustained fatal injuries. While each of these fatalities is tragic, the number of school bus occupant fatalitie is small compared to the number of occupant fatalities to children in other types of vehicles. For example, in 1989 there were 5,287 deaths among children aged five to 18 in vehicles other than school buses. In 1977, NHTSA issued Federal motor vehicle safety standard No. 222, School Bus Passenger Seating and Crash Protection, which established minimum crash protection levels for occupants of all school buses. For large school buses, those with a gross vehicle weight rating (GVWR) above 10,000 pounds, the standard requires occupant protection through a concept called "compartmentalization" -- strong, well-padded, well-anchored, high-backed, evenly spaced seats. The effectiveness of "compartmentalization" has been confirmed by independent studies by the National Transportation Safety Board (NTSB) and the National Academy of Sciences (NAS). Under the current requirements of Standard No. 222, small school buses, those with a GVWR of 10,000 pounds or less, must provide "compartmentalization" and be equipped with lap or lap/shoulder belts at all designated passenger seating positions. The agency believes that safety belts are necessary in addition to "compartmentalization" in small school buses because of their smaller size and weight, which are closer to that of passenger cars and light trucks. In 1987, the NTSB completed a study of the crashworthiness of large school buses, and concluded that most school bus occupant fatalities and serious injuries were "attributable to the occupants' seating position being in direct line with the crash forces. It is unlikely that the availability of any type of restraint would have improved their injury outcome." In 1989, NAS completed a study of means to improve school bus safety and concluded that "the overall potential benefits of requiring seat belts on large school buses are insufficient to justify a Federal requirement for mandatory installation. The funds used to purchase and maintain seat belts might better be spent on other school bus safety programs and devices that could save more lives and reduce more injuries." The NAS pointed out that since children are at greater risk of being killed in school bus loading zones (i.e., boarding and leaving the bus) than on board school buses, "a larger share of the school bus safety effort should be directed to improving the safety of bus loading zones." A summary of the NAS report is enclosed. In response to the recommendations from the NAS study, NHTSA has initiated several rulemaking actions, such as improvements to school bus visibility by the driver and requiring stop signal arms on school buses, designed to improve the safety of students in school bus loading zones. Besides the actions taken in response to the NAS study, NHTSA has initiated several other rulemaking activities to improve further the safety of school buses, e.g., increasing the number of emergency exits, establishing wheelchair securement/occupant restraint requirements, and improving the body joint strength requirements. While there are no Federal requirements for safety belts on large school buses, states are free to install them if they feel it is in the best interest in their state. However, as noted in the NAS report, if the safety belts are to be beneficial, "states and local school districts that require seat belts on school buses must ensure not only that all school bus passengers wear the belts, but that they wear them correctly." In summary, the safety record of school buses is outstanding. As such, there is no compelling evidence to suggest that safety belts would provide even higher levels of occupant crash protection. Also, the agency agrees with the conclusion from the NAS report, that there is insufficient reason for a Federal mandate for safety belts on large school buses. I hope you find this information helpful. ATTACHMENT TRB REPORT SUMMARY, DATED MAY, 1989, ENTITLED SPECIAL REPORT 222-IMPROVING SCHOOL BUS SAFETY. (TEST OMITED) |
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ID: aiam0698OpenMr. Bernard Belier, U.S. Resident Engineer, CITROEN, 801 Second Avenue, New York NY 10017; Mr. Bernard Belier U.S. Resident Engineer CITROEN 801 Second Avenue New York NY 10017; Dear Mr. Belier: This is in reply to your letter of April 24, 1972, in which you pose questions about the operation of the seat belt warning system under Standard 208 and about the intent of the headlamp adjustment requirement under Standard 215.; Your questions on Standard 208 deal with the requirement in S7.3.3 tha the warning system in a vehicle with an automatic transmission must not operate when the engine is operating and the gear selector is in the 'Park' position. In answer to your first question, if the two conditions for non-operation exist, the warning system must not operate, regardless of the position of the hand brake lever. If either condition does not exist, e.g., the transmission is in 'Park' but the engine is not operating, it would be permissible to have the system operate, and its operation could be controlled by the hand brake so long as the hand brake circuitry does not interfere with the mandatory operation of the system under S7.3.1 and S7.3.5.; If the shift lever is in the neutral position, as stated in your secon question, you are free to choose whether to have the system operate or not, since S7.3 does not require either operation or non-operation when the transmission is in neutral.; In response to your last question on Standard 208, an 'operatin engine' is an engine that is rotating. It is permissible to have a system in which the warning operates when the transmission is in 'Park' and the ignition is 'On', but the warning must shut off when the engine begins to operate.; The other operating mode of your system has no direct counterpart i Standard 208. As you describe it, returning the ignition to the 'off' position will activate the warning system, even after removal of the key, until the belts are returned to their stowed positions. Our letter of August 17, 1972, explained that this will not conform to the requirement of S7.3.2 that the warning must not operate when the belts at occupied front positions have been operated.; We recognize that there are other possible alternatives to the require interlock system as a means of encouraging seat belt usage, and several have been suggested. We consider it important, however, that these systems work in a substantially uniform manner, for maximum public safety, acceptance and convenience. On the basis of all the material we have received to date, including yours, we have decided that our present requirements represent the best combination for the alternative to passive restraints in the period 1973-1975. I therefore must deny your petition to substitute your system, or allow it as an alternative, for the interlock system.; Sincerely, Douglas W. Toms, Administrator |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
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