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: aiam4980OpenMr. Robert Salton Performance Friction Corp. 83 Carbon Metallic Highway P.O. Box 819 Clover, S.C. 29710-0819; Mr. Robert Salton Performance Friction Corp. 83 Carbon Metallic Highway P.O. Box 819 Clover S.C. 29710-0819; "Dear Mr. Salton: This responds to your request for an interpretatio of Federal Motor Vehicle Safety Standard No. 105, Hydraulic Brake Systems (49 CFR 571.105). You stated that you are unclear about the pedal force requirements during the first fade and recovery test baseline check stops, and that an interpretation would make it clear exactly what calculation of pedal effort is used to verify compliance during the fade and recovery check stops. You also asked what values of pedal effort would be 'considered non-compliance,' i.e., whether peak, average or sustained control force must be within the specified limits under section S5.1.4.1. You indicated in a telephone conversation with Edward Glancy of my staff that you are primarily interested in the requirements for vehicles with a GVWR less than 10,000 pounds. Your questions are addressed below. By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with applicable standards. A manufacturer then certifies that its vehicles or equipment comply with the applicable standards. Standard No. 105's fade and recovery requirements are set forth in S5.1.4. These requirements must be met under the conditions prescribed in S6, when tested according to the procedures set forth in S7. See S5.1. The standard specifies two fade and recovery tests, each of which consists of three parts: (1) baseline check stops or snubs, (2) fade stops or snubs (the heating cycle), and (3) recovery stops or snubs. The pedal force requirements for the baseline check stops or snubs are set forth in S5.1.4.1, which reads as follows: The control force used for the baseline check stops or snubs shall be not less than 10 pounds, nor more than 60 pounds, except that the control force for a vehicle with a GVWR of 10,000 pounds or more may be between 10 pounds and 90 pounds. S5.1.4.1 must be read in conjunction with S7.11.1, which sets forth the procedure for the baseline check stops or snubs. S7.11.1.1 provides the following procedure for vehicles with a GVWR of 10,000 pounds or less: Make three stops from 30 mph at 10 fpsps for each stop. Control readings may be terminated when vehicle speed falls to 5 mph. Average the maximum brake control force required for the three stops. The baseline check stops or snubs are thus made at a constant deceleration (10 fpsps), with the control force varying as necessary to maintain that constant deceleration. Under S5.1.4.1, the control force is required to stay within a prescribed range (10 pounds to 60 pounds for vehicles with a GVWR less than 10,000 pounds) throughout the entire stop or snub (from the time in which application is started until the vehicle speed falls to 5 mph, other than the initial momentary period it takes to go from 0 to 10 pounds). Thus, compliance with S5.l.4.1 is not determined based on peak, average or sustained control force. Instead, for a vehicle to comply with this test, the control force must never fall below 10 pounds or be above 60 pounds during any part of the test (for the period described above). Your other question concerned how calculation of pedal effort during the baseline check stops or snubs is used to verify compliance during the fade and recovery check stops. As indicated above, S7.11.1.1 specifies that an average is taken of the maximum control force for the three stops. The term 'maximum' refers to the peak control force for each of the stops. I note that this average is not related to whether the vehicle complies with S5.1.4.1. Instead, as discussed below, this average establishes a baseline control force, which is used to derive certain of the control force limits for the recovery stops. The requirements for the recovery stops are set forth in S5.1.4.3, which reads as follows: Each vehicle with a GVWR of 10,000 pounds or less shall be capable or making five recovery stops from 30 mph at 10 fpsps for each stop, with a control force application that falls within the following maximum and minimum limits: (1) A maximum for the first four recovery stops of 150 pounds, and for the fifth stop, of 20 pounds more than the average control force for the baseline check, and (2) A minimum of-- (A) The average control force for the baseline check minus 10 pounds, or (B) The average control force for the baseline check times 0.60, whichever is lower (but in no case lower than 5 pounds). . . . Thus, the minimum and (for one stop) the maximum control force limits for the recovery stops are calculated using the average control force for the baseline check stops or snubs. This average control force is the one calculated under S7.11.1.1 using the maximum control force of each of the baseline check stops or snubs. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: 10-005859 df samaniOpenMr. Nasser Zamani, Senior Manager Compliance and Regulatory Affairs Daimler Trucks North America LLC 4747 N. Channel Ave. Portland, OR 97217-7699 Dear Mr. Zamani: This responds to your request for assurance that we will apply a tolerance when measuring the width of flexible occupant seats, in testing school buses for compliance with Federal Motor Vehicle Safety Standard (FMVSS) No. 222, School bus passenger seating and crash protection. We regret to inform you that this letter is unable to provide a tolerance. You ask about a flexible occupancy seat, which is defined in S4 of FMVSS No. 222 as: a bench seat equipped with Type 2 seat belts that can be reconfigured so that the number of seating positions on the seat can change. The seat has a minimum occupancy configuration and a maximum occupancy configuration, and the number of passengers capable of being carried in the minimum occupancy configuration must differ from the number of passengers capable of being carried in the maximum occupancy configuration. S4.1 of FMVSS No. 222 specifies how the National Highway Traffic Safety Administration (NHTSA) will determine the number of seating positions and seat belt positions on a bench seat, including flexible occupancy seats. S4.1(c) states: Except as provided in S4.1(d), the number of Type 2 seat belt positions on a flexible occupant seatis expressed by the symbol Y, and calculated as the seat bench width in millimeters [(mm)] divided by 380 and rounded to the next lowest whole number. See Table 1 [of the standard] for an illustration. S4.1(d) states: A flexible occupancy seat meeting the requirements of S4.1(c) may also have a maximum occupancy configuration with Y +1 Type 2 seat belt positions, if the minimum seat bench width for this configuration is Y +1 times 330 mm. See Table 1 [of the standard] for an illustration. (Emphasis added.) Request for Tolerances You indicate that your flexible occupancy seat has an occupancy configuration of two Type 2 seat belt positions large enough for mid-size adult males under S4.1(c) and an occupancy configuration of three seat belt positions for smaller passengers under S4.1(d). Under S4.1(d), the minimum seat width for the maximum occupancy configuration is 990 mm (3 x 330 mm). You would like the seat width to be permitted to be slightly less than 990 mm wide. You state that since it is difficult to control the tolerance of cushions, the average seat bench width would have to be greater than 990 mm in order to ensure the cushions produced never measured less than 990 mm. You are worried that if the seat bench width is greater than 990 mm, the bus aisle width would be less than 305 mm, which might not meet some State and local requirements. To avoid the difficulties of manufacturing soft goods, you ask if we apply tolerances to the measurement of seat bench width. You suggest that, Tolerances on soft good of this nature are typically +/- 13 mm. Response We regret to inform you that we cannot issue an interpretation along the line you suggest. NHTSA cannot provide variations from the explicit requirements of the FMVSSs through our interpretation letters. This is because under the National Traffic and Motor Vehicle Safety Act (49 U.S.C. Chapter 301; the Safety Act), NHTSA must establish by order appropriate safety standards. The Administrative Procedure Act (APA) applies to all orders establishing, amending, or revoking a safety standard. The APA generally requires agencies to publish a notice setting forth the proposed change to a safety standard, and allow the public to comment thereon, before the agency can adopt any change to the established safety standard. Our interpretation letters are not subject to the requirements for public notice and comment, because interpretations do not add, delete, or change any requirements established in a safety standard. Instead, our interpretations explain how the requirements established in safety standards or the Safety Act apply to particular vehicles or equipment, or otherwise clarify the meaning of the established requirements. In this case, S4.1s language is clear. Under S4.1(d), a flexible occupancy seat (bench seat) may have a maximum occupancy configuration with Y +1 Type 2 seat belt positions, if the minimum seat bench width for this configuration is Y +1 times 330 mm. Thus, under the standard, the minimum seat bench width for your flexible occupancy seat is 990 mm (3 x 330 mm=990 mm). We cannot interpret this language to include a tolerance of +/- 13 mm for the bench.[1] Your letter suggests a change to the requirements of FMVSS No. 222, not a clarification of those requirements. We cannot change those requirements without initiating rulemaking and giving the public notice of and the opportunity to comment on the change. We also note that interpreting the standard to include a tolerance would confuse the meaning of Table 1 of the standard. Table 1 illustrates the number of seating positions as a function of seat bench width. The table shows that a seat bench with a width of 990-1139 mm would have a minimum of two seating positions (fixed occupancy seats or flexible occupancy seats), and for flexible occupancy seats, a maximum occupancy configuration of three seating positions. The table also shows that a seat bench with a width of 760-989 mm would have a minimum of two seating positions (fixed occupancy seats or flexible occupancy seats), and a maximum occupancy configuration of two seating positions. If we applied a tolerance of +/- 13 mm as you suggest, a bench seat of 760-989 mm nominal width could have a maximum occupancy of two or three seating positions. An interpretation that 990 mm means some lesser value would render the values in Table 1 confusing. For the above reasons, we cannot interpret FMVSS No. 222 to provide the tolerance you seek. Sincerely, O. Kevin Vincent Chief Counsel Ref: Std. No. 222 8/17/2011 [1] We assume you meant +/- 13 mm for the entire 990 mm bench and not per 330 mm seating position, but it is unclear from your letter. |
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ID: 14896-4.pjaOpenMr. Charles Jandecka Dear Mr. Jandecka: I apologize for the delay in responding to your letter requesting a reevaluation of Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205), as it relates to tinting of windows. Specifically, you expressed concern about the increase in the number of vehicles with dark-tinted windows. As you know, Standard No. 205 requires vehicle windows that are "requisite for driving visibility" to meet a 70 percent light transmittance requirement. Darker windows are currently allowed in the rear and rear side windows on trucks, buses, and multi-purpose vehicles (MPVs) because the agency has issued an interpretation stating that these windows are not requisite for driving visibility. You would like the National Highway Traffic Safety Administration (NHTSA) to prohibit dark-tinted windows in light trucks, MPVs, and vans. You disagree with the conclusion of the agency's interpretation that these windows are not requisite for driving visibility. In addition, you argue that sport utility vehicles and vans should not be relieved of the light transmittance requirement by the interpretation because they do not meet the definition of an MPV. An MPV is ". . . constructed either on a truck chassis or with special features for occasional off-road operation." 49 CFR 571.3. I will first address your argument regarding classification of vehicles. In contending that these vehicles are not MPVs, you argued that sport utility vehicles were not "off-road vehicles," which you found defined in Executive Order No. 11644 and 16 USC 670. We note that these authorities are not relevant to our regulations. But more importantly, this argument fails to recognize the distinction between a "vehicle with features for occasional off-road operation," and a more capable "off-road vehicle." The definition for off-road vehicles, such as the Humvee, is not relevant to whether vans and sport utility vehicles are MPVs. Sport utility vehicles clearly meet the MPV definition. They have "special features for occasional off-road operation" such as four-wheel drive, large all purpose tires, large suspension excursions, and high ground clearances. The fact that they offer interior amenities and are often not driven off-road by their owners does not nullify these special features. The classifications are based on design, because ultimate use is something the manufacturer generally does not know. The presence of some of these features on vehicles certified as passenger cars also does not nullify their presence on sport utility vehicles. Some vans and minivans meet the definition of trucks. Most cargo vans are classified as "trucks" under our safety standards. A truck is defined in 49 CFR 571.3 as being ". . . designed primarily for the transportation of property or special purpose equipment." Many full-size vans are designed on a chassis that may be fitted with any number of body types and is designed and used primarily for carrying cargo. Most passenger vans and minivans are classified as "multipurpose passenger vehicles," because they are considered by their manufacturers to be "constructed on a truck chassis." Some manufacturers may classify them as MPVs because of heavier running gear, front suspensions, and rear leaf springs, for greater load-carrying capacity. In addition, the rear seats are often removable for carrying large cargo rather than passengers, supporting a colloquial definition of "multi-purpose" vehicles. Generally speaking, designation of the vehicle type is up to the manufacturer. The definitions of trucks and MPVs overlap somewhat. NHTSA's main concern is that all vehicles meet the standards applicable to the type of vehicle as which they are certified. The agency is aware that in recent years changes in the construction of minivans and sport utility vehicles have tended to blur the line between these vehicles and passenger cars. There has been a convergence in the safety standards applicable to these vehicles and the standards applicable to passenger cars. NHTSA has not tried to create a complex distinction between these vehicle types, but has instead allowed the industry to produce innovative designs that meet the demands of the marketplace. Moreover, the manufacturers have for many years continued classifying vans and minivans as light trucks for the purpose of complying with the Corporate Average Fuel Economy (CAFE) requirements. The vehicle classification requirements in 49 CFR 523.5(a)(5) allow manufacturers to properly classify vans and minivans with removable seats as light trucks for that purpose. It is doubtful the industry could comply with the CAFE standards if NHTSA suddenly restricted classification capabilities. Therefore, given the industry's longstanding reliance on NHTSA's interpretation and regulation in this area, this office cannot make a such a drastic change in the context of an interpretation letter. Turning now to your question of whether the rear and rear side windows of sport utility vehicles and vans should be considered "requisite for driving visibility," we continue to believe that they should not be. You correctly identified a change in the agency's opinion between the July 16, 1973 interpretation of Richard Dyson and the April 4, 1985 interpretation of Jeffrey Miller, which first announced the conclusion that these windows were not requisite for driving visibility. However, you are incorrect to conclude that either the January 9, 1990 interpretation by Stephen Wood, or any of the subsequent interpretations you cited represent a change in the agency's position on the matter. Mr. Miller's interpretation still represents the agency's position. The reasoning behind the Miller interpretation is that these vehicles are often sold in configurations without windows or with small windows to the rear of the driver (e.g., a panel van). Even if the windows to the rear of the driver are large enough, these vehicles may frequently carry loads that block the view out of them. Logically, it is impossible to argue that these windows are requisite for driving visibility when they do not even exist on the next van on the lot. In addition, most minivans and sport utility vehicles today, (even those with larger side windows and without a vision-blocking load) have rear side windows that are too high to rely on for lane changes. Vehicle manufacturers provide right-side rear view mirrors on these vehicles which assist in lane changes. If these windows were requisite for driving visibility, one might expect that vehicle types with darker glass in those locations would be more involved in crashes, but the data do not show this to be true. Some analyses have shown that they are generally less involved in crashes than passenger cars, and that they are even under-involved in lane change crashes. This indicates that the existing window and mirror systems are meeting the minimum needs for driving visibility. On January 22, 1992, NHTSA proposed, among other things, transmittance requirements for the windows to the rear of the driver in these vehicles. The proposed requirements would permit windows darker than those in passenger cars, but would require these windows to be lighter than the "privacy glass" currently being sold on some minivans and sport utility vehicles. Comments on the proposal were overwhelmingly negative. The law enforcement community was divided on the issue. Final action on this rulemaking is anticipated soon. I hope this information is helpful. If you have any further questions, please feel free to contact Paul Atelsek of my staff at this address or by telephone at (202) 366-2992. Sincerely, |
1998 |
ID: nht91-1.9OpenDATE: January 3, 1991 FROM: Jim Holperin -- State Representative, 34th Assembly District TO: Taylor Vinson -- Legal Counsel, NHTSA TITLE: None ATTACHMT: Attached to letter dated 2-26-91 from Paul Jackson Rice to Jim Holperin (A37; Std. 108) TEXT: I write today on behalf of LeRoy E. Mueller, President of the Wisconsin Trailer Company, Inc. in Phelps, Wisconsin. Mr. Mueller's company recently submitted a bid to the Wisconsin Department of Natural Resources for two tilt-deck trailers based on the enclosed specifications. As Mr. Mueller is concerned that if he builds the trailers exactly to specifications that they will be in violation of Title 49, Section 571-108 and, by cross reference, in violation of relevant SAE requirements. Kevin Cavey recommended I direct this correspondence to you and request a determination from the NHTSA regarding whether our DNR's trailer specifications comply with Title 49 and relevant SAE codes. I am also enclosing a letter from Mr. Mueller indicating his primary concern lies with what appears from the specifications to be a permanent, stationary ramp which Mr. Mueller believes might obscure a clear view of the trailer's tail lights from a 45 degree angle as required by Title 49 and SAE codes. I would appreciate it if you could take time to review the enclosed material and determine whether Mr. Mueller's concerns regarding an obstructed view of the tail light are legitimate or not. Thank you for giving this request your consideration and, of course, if there is additional information you need please do not hesitate to contact me by letter or phone.
Attached to a map of the 34th Assembly District (Text omitted)
Attachment Specification 8 SPECIFICATION TYPE: (2) Two 26,000 lb. minimum payload capacity "over the wheel" tilting platform trailer. DELIVERY: The successful bidder shall deliver all units ordered, after final inspection and approval by DNR personnel, to DNR, Neil H. LeMay Forestry Center, 518 West Somo Ave., Tomahawk, WI 54487, and to arrive during regular working hours - Monday thru Friday, 7:45 a.m. to 11:45 a.m. and 12:30 p.m. to 4:30 p.m. Advance notice of at least one day shall be given. The successful bidder shall arrange for and pay transportation costs for the delivery of all units ordered.
USE: Trailer will be used to transport medium sized crawler tractors with fire plows, heavy duty wheel tractors, and farm-type machinery, both on and off the road, maximum highway speed will be 55 MPH. A. CAPACITY: 26,000 lb. minimum payload capacity. When unloaded, there shall be sufficient tongue weight to enable the unit to be towed without fish-tailing. OUTLINE DRAWING - T-D169-401 Issue 02 B. PLATFORM: Length - 20 feet Width - 94" minimum - 96" maximum Height - 38" maximum fully loaded FRAME: Steel shall be designed with ample safety factor and electrically welded where steel meets steel. All crossmembers are to be in line, fully welded on top, sides, and bottom, both on the inside and outside of the main frame. DECK: Full 2 inch thick treated apitong wood deck. The entire rear 7 feet of the trailer to be ribbed traction bed with 3.75" x 2" x 3" angle steel ribs replacing the wood deck planking. Ribs to be spaced 7" on center with the 3" leg facing the front of the trailer. All wheel well openings shall be covered. Area around wheel wells shall be reinforced to support deck. ANGLE IRON LOADING GUIDES: Locate three removable angle iron guides on top of deck per outline drawing. Stake pockets, footholds, expanded metal walkway, tie-down slots per outline drawing. LOADING RAMPS: 0.50" thick steel formed loading ramps per outline drawing. PLATFORM LOCK: Shall be heavy duty screw type, self adjusting for wear, and shall hold the platform tight and rattle free in the closed position, The end of the screw shall be wedge shaped for ease of engagement. OPERATION: Deck to tilt open or closed with 150 lb. weight, allowing loading or unloading of equipment. Loading angle shall not exceed 15 degree incline. Zerk type grease fittings shall be on all platform tilt pivot points.
SPECIFICATION CUSHIONING DEVICE: One (1) 4" hydraulic cylinder with 1.25" diameter rod, or two (2) 2.5" hydraulic cylinders with 1" diameter rod (all minimum dimensions) designed to cushion the opening and closing the platform. When cylinders are completely open, the bed of trailer shall be capable of tilting 4" minimum below ground level in the tiltbed position. C. SUSPENSION: Single point spring suspension - Neway USR 444, or equal - able to maintain equal ground pressure while traveling over uneven terrain. AXLE LOCATION: Distance from center of axles to front of trailer bed to be approximately 10 feet. TIRES: Nine (9) 7.5 x 15 L.R. "F" (12PR) low platform trailer tube type tires and rims capable of meeting load and speed requirements of this specification as noted in item A. One (1) tire to be mounted on spare rim. Valve extensions required on inside tires. WHEEL: Budd disc wheels. Stemco oil wheel seals shall be furnished on all axles. AXLES: Full width through type axles with one (1) hubometer. D. BRAKES: Full air complete with all lines, breakaway control valve, and air reservoir tank with 1,000 cubic inch minimum capacity. Air brake hoses to extend a minimum of 24" ahead of the pintle eye and shall be complete with couplings. Air lines shall not be interchangeable. Left gladhand shall be the emergency air line Velvac #55B-13. Right hand gladhand shall be the service air line Velvac #55B-14. Brake system shall meet SAE and DOT requirements. All wheel brakes to be 12.25" x 7.5" minimum. Gladhand holders are required for brake lines when they are not in use, and are to be mounted near tongue. Include piggy back parking with mechanical release and mechanical release tool. E. ELECTRICAL SYSTEM: Shall be per writing diagram T-AO86-701 furnished as a part of this specification. WIRING: Shall meet all SAE, ICC, and DOT requirements. All wires shall be in loom, heavy jacket, or conduit and mounted in a protected position. Where wires pass through steel, they shall be protected with rubber grommets. Two (2) feet of conductor wire, ahead of pintle, shall be installed in the female plug for connection to the towing vehicle. No aluminum rivets for grounds are allowed. LIGHTS: Lights shall meet SAE, ICC, and DOT requirements. Lights shall be in protected recesses or with protective base around lights. All lights shall be of the plug-in type. SIX POLE PLUG: Vel Vac #59P-6 (6 way male plug) with replaceable interior, or equal.
Attached to drawings and photos of Lid Trailer (Text and graphics omitted) |
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ID: 1983-3.29OpenTYPE: INTERPRETATION-NHTSA DATE: 12/01/83 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Mazda Inc. -- H. Nakaya TITLE: FMVSR INTERPRETATION TEXT: Dear Mr. Nakaya:
This responds to your October 13, 1983 letter regarding the classification of certain hypothetical mini-van models as either passenger cars, multipurpose passenger vehicles, or trucks for purposes of complying with Federal motor vehicle safety standards.
Your first question involved the effect of changes in floor pan geometry on this classification. You postulate separate cargo and passenger versions of the mini-van, with each version using identical suspension, steering and driveline components and each vehicle being of unibody construction. However, slight differences would exist in the floor pans of the two vehicles, with the passenger version having a lowered floor pan section to accommodate the rear seat.
Assuming that the cargo version has greater cargo-carrying volume than passenger carrying volume (see, e.g., 49 CFR part 523), we would consider that version to be a truck. (In the unlikely event the cargo version does not have that ratio of volumes, all versions of the mini-van would probably be considered passenger cars.) Since the passenger version of a mini-van would almost certainly have greater passenger-carrying volume than cargo carrying volume, that vehicle would be treated as a passenger car unless it meets the agency's "multipurpose passenger vehicle" definition. That definition provides, in relevant part, that an MPV is a motor vehicle designed to carry 10 people or less and which is constructed on a "truck chassis." The "chassis" of a vehicle includes the vehicle's power train as well as its entire load supporting structure. In the case of a vehicle using unibody construction, this load supporting structure would technically include the floor pan.
The fact that a common chassis is used in a family of vehicles, one member of which is classified as a "truck," is evidence that the common chassis is a "truck chassis." However, further evidence is needed to demonstrate that the chassis has truck attributes, such as information showing the design to be more suitable for heavy duty, commercial operation than a passenger car chassis. This further evidence is necessary since otherwise the introduction of a cargo carrying version of an existing passenger car could result in the reclassification of the passenger car into an MPV, if the agency only considered the issue of whether a common chassis is used. For example, in the past, certain station wagons have been marketed without rear seats and with other modifications which render them the functional equivalent of a cargo van. The agency does not believe it to be appropriate in such a situation to reclassify the basic station wagon as an MPV.
The floor pan differences mentioned in your first question do not appear to be so significant as to require treating the two mini-van versions as having different chassis. The agency does not consider minor floor pan differences to negate the fact that two versions of the same family of vehicles employ the same "chassis," since to do so would likely mean that no unibody vehicles could be classified as MPV's. However, in the absence of any information regarding the extent to which the common chassis has truck-like attributes, we cannot state whether the vehicle would be treated as an MPV.
Your second question involves the effect of various seating designs on whether a unibody constructed mini-van is classified as an MPV. Since the seats are not part of the vehicle chassis, these variations should have no impact on whether the vehicle is an MPV. (Fuel economy classifications are dependent on seat configuration however--see 49 CFR Part 523.)
Your third question involves the significance of the relative sales levels, order of introduction, and actual existence of two versions (cargo and passenger) of the mini-van. In theory, a passenger version of a mini-van could be classified as an MPV even if no cargo version were offered in the U.S. or indeed if none were ever produced. In such a situation, however, the manufacturer would be under a heavy burden to demonstrate that what is sold as a passenger carrying vehicle in fact has a "truck chassis," with heavy duty, commercially suited attributes. The existence of a truck version, and the fact that the truck version was either designed first or was the principal focus of the design would be additional factors which would tend to indicate that the chassis is a truck chassis.
If you have further questions in this matter, please contact us. Sincerely,
Frank Berndt Chief Counsel October 13 1983
Mr. Frank Berndt Chief Councel National Highway Traffic Safety Administration 400 Seventh Sreet, S .W. Washington, D. C. 20590
Dear Mr. Berndt :
A great deal of confusion exists in the automotive industry concerning the precise classification of 'mini-vans'. Specifically, these vehicles could be classified as passenger vehicles, multipurpose vehicles (MPV), or light-duty trucks (LDT), depending on the criteria applied. Mazda (North America), Inc. is interested in this subject and has a number of items that have not been satisfied by existing definitions.
Please examine the following questions and respond to relevant safety compliance implications, if any.
1. Existing standards (MVSS ? 571.3 (b)) indicate the criteria for a multipurpose vehicle as being 'constructed either on a truck chassis or with special features for occasional off-road use'. Assuming the original truck is of unibody construction --a) Is the same chassis considered in the modification of the floor pan from LDT to MPV? (See Sketch 1).
b) What impact would floor pan geometry modification from the truck versions to the MPV version have on MPV classification, assuming identical suspension, steering and driveline components? c) Can a common floor pan be used for both the truck version and the MPV version, with the addition of a flat platform in the truck version --
1) Bolted in place (removable)?
2) Welded in place (permanent)? (See Sketch 2).
2. Assuming the original truck is of unibody construction, what influence does the rear seating design have on MPV classification if the additional seating configurations are -- a) Pedestal assemblies bolted to the floor pan that when removed result in a flat surface? (See Sketch 3).
b) Attached seat cushion and back assemblies that fold forward together at a single pivot with respect to the floor pan result in a flat surface? (See sketch 4).
c) Separate seat cushion and back assemblies that fold forward sequentially at two pivot points resulting in a flat surface? (See Sketch 5).
d) Fold down seat backs attached at the pivot point to a stationary seat cushion resulting in a flat surface? (See Sketch 6).
3. If a MPV classification is desired as 'derived' from a truck chassis --
a) Assuming the engineering, design, tooling, testing, etc. is completed for the truck version, must the truck version be built at al1 to insure MPV classification?
b) Assuming a truck version must be introduced, can the MPV version be introduced first followed by a later truck version introduction?
c) Assuming a truck version must be introduced, can the truck and MPV be introduced simultaneously?
d) Assuming a truck version must be introduced, must the truck be introduced in the United States market to insure MPV classification?
e) Assuming a truck version must be introduced, does the proportion of truck versus MPV versions sold influence the MPV classification if --
1) Both versions are sold in the United States?
2) Only the MPV version is sold in the United States?
Thank you for your help in this important matter. Very truly yours,
H. Nakaya Manager
HN/ab
cc:Mr. R. Fairchild
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ID: aiam4591OpenMabel Y. Bullock, Esq. Assistant Attorney General State of North Carolina Department of Justice P. O. Box 629 Raleigh, NC 27602-0629; Mabel Y. Bullock Esq. Assistant Attorney General State of North Carolina Department of Justice P. O. Box 629 Raleigh NC 27602-0629; "Dear Ms. Bullock: Thank you for your letter to Ms. Susan Schruth of m staff, regarding North Carolina General Statute 20-127, Windshields must be unobstructed. I regret the delay in responding. You enclosed a copy of the statute, the regulations implementing it, a copy of a December 18, l987 legal memorandum prepared by your department concluding that a State statute or regulation allowing 35% light transmittance through windows in motor vehicles would be preempted by current Federal safety laws and standards regulating this same subject matter, and a copy of a May 6, 1988 letter from the Motor and Equipment Manufacturers Association (MEMA) to Mr. William S. Hiatt, the Commissioner of Motor Vehicles for North Carolina, asserting that the North Carolina statute was not preempted by Federal laws and regulations. You asked for my opinion as to whether the North Carolina statute conflicts with any provision of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. /1381 et seq.) or with the Federal Motor Vehicle Safety Standards (49 CFR 571.1 et seq.). Some background information on Federal motor vehicle safety laws and regulations may be helpful. As you are aware, our agency is authorized, under the National Traffic and Motor Vehicle Safety Act, to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. One of the standards that we have issued under this authority is Standard No. 205, Glazing Materials (49 CFR /571.205), which applies to all new vehicles and all new glazing materials for use in motor vehicles. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance (70 percent light transmittance in areas requisite for driving visibility, which includes all windows in passenger cars). Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) specifies that, 'No person shall manufacture for sale, sell, offer for sale, or introduce or deliver for introduction in interstate commerce, or import into the United States, any motor vehicle or item of motor vehicle equipment manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect under this title unless it is in conformity with such standard ...' Because of this statutory requirement, any manufacturer, importer, or dealer that installs solar films or other sun screen devices on new glazing materials or the glazing installed in new vehicles must certify that the vehicle continues to comply with the light transmittance and other requirements of Standard No. 205. The requirement that a car comply with all applicable safety standards applies only until the car is first sold to a consumer. See section 108(b)(1) of the Safety Act (15 U.S.C. 1397(b)(1)). Both before and after a vehicle is first sold to a consumer, any modifications to the vehicle's windows, including tinting, are affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits any manufacturer, dealer, distributor, or repair business from 'rendering inoperative' any device or element of design installed in a vehicle in compliance with any safety standard. In the case of windows in a passenger car, this means that no manufacturer, dealer, distributor, or repair business could install a sun screen device or window tinting that would result in a light transmittance of less than 70 percent for any window of the car, or otherwise cause the car to no longer comply with the other requirements of Standard No. 205. Violations of this 'render inoperative' prohibition can result in Federal civil penalties to the manufacturer, dealer, distributor, or repair business of up to $1000 for each noncomplying installation. Please note that Federal law does not affect vehicle owners. Vehicle owners may alter their own vehicles and operate them on the highways as they please, even if the vehicle's windows no longer comply with the requirements of Standard No. 205. Hence, no provision of a Federal statute or this agency's regulations prevents individual vehicle owners themselves from tinting the windows on their vehicles. The authority of States to regulate glazing is affected by section 103(d) of the Safety Act (15 U.S.C. /1392(d)). This section provides that: w henever a Federal motor vehicle safety standard established under this title is in effect, no State or political subdivision of a State shall have any authority either to establish, or to continue in effect, with respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard. Nothing in this section shall be construed as preventing any State from enforcing any safety standard which is identical to a Federal safety standard. The effect of this provision of the Safety Act, with respect to the light transmittance requirements of Standard No. 205, is to expressly prohibit any State from specifying some level of light transmittance other than the 70 percent specified in Standard No. 205 for new motor vehicles and new glazing for use in motor vehicles. Each of the individual States has authority to enforce identical standards (i.e., a minimum of 70 percent light transmittance) for new motor vehicles and new glazing for use in motor vehicles. Additionally, each of the individual States has the authority to regulate the modifications that may be made to vehicles by their owners and to establish requirements for vehicles to be registered in that State. Having provided this background, we want to turn now to the results of our review of the North Carolina statute and regulations, along with your office's memorandum concluding that the statute is preempted by Federal law. 1. New vehicles and new glazing for use in vehicles. We concur with the conclusions in your memorandum that the North Carolina statute would be preempted if it specifies any requirements other than the requirements of Standard No. 205 (minimum of 70 percent light transmittance) for new vehicles or for new glazing for use in motor vehicles. Section 108(a)(1) of the Safety Act and Standard No. 205 require all new vehicles and new glazing for use in motor vehicles to be delivered to the first purchaser with a light transmittance of at least 70 percent. Section 103(d) of the Safety Act expressly preempts any non-identical State standard on the subject of window tinting. Section 20-127(d) of the North Carolina statute appears to permit a single application of tinted film with a light transmittance of as little as 35 percent to be applied to vehicle glazing after factory delivery, but before sale to the public. This provision is preempted by Federal law, as is any other provision of North Carolina law which specifies that new glazing and glazing in new vehicles shall have some level of light transmittance other than the 70 percent minimum light transmittance requirement specified in Standard No. 205. 2. Modifications to vehicles and glazing by manufacturers, distributors, dealers and repair businesses after the first purchase of the vehicle or glazing in good faith for purposes other than resale. We concur with the conclusions in your memorandum that the North Carolina statute would be preempted by Federal law if it permits the commercial installation of sunscreen materials so that the combination of the sunscreen material and the existing glazing no longer meet the 70 percent light transmittance requirement specified in Standard No. 205. This conclusion is based on the conflict between the North Carolina statute and the 'render inoperative' provision of section 108(a)(2)(A) of the Safety Act. That provision prohibits any manufacturer, distributor, dealer, or repair business from rendering inoperative the compliance of a vehicle or an item of glazing with any of the requirements of Standard No. 205, including the minimum 70 percent light transmittance requirement. Apart from the issue of preemption, I want to note that the provisions of State law cannot alter the effect of the 'render inoperative' prohibition in Federal law. Regardless of how North Carolina law treats the combination of the glazing and the tinting, if it results in less than 70 percent light transmittance, a manufacturer, distributor, dealer, or repair business that installed such tinting on a vehicle would be liable for the Federal civil penalty discussed above. 3. Modifications to vehicles and glazing by individual owners themselves after the first purchase of the vehicle or glazing in good faith for purposes other than resale. As noted above, Federal law does not regulate modifications that individual owners themselves make to their vehicles or glazing after the first purchase in good faith for purposes other than resale, even if those modifications result in the vehicles or glazing no longer complying with the requirements of Standard No. 205, including the requirement for at least 70 percent light transmittance. The State of North Carolina is free to establish whatever restrictions, if any, it deems appropriate on individual owner modifications, without regard to the requirements of Standard No. 205. To the extent that the North Carolina statute seeks to address these individual owner modifications, it would not be preempted by Federal law. 4. Requirements for vehicles to be registered in the State of North Carolina. An individual State is free to establish whatever requirements it deems appropriate for vehicles to be registered in the State, provided that those State requirements would not prohibit the registration of vehicles that complied with the requirements of the Federal safety standards. Thus, the State of North Carolina is free to permit vehicles that do not comply with the requirements of Standard No. 205 to be registered in North Carolina. To the extent that the North Carolina window tinting statute seeks to establish requirements for vehicles to be registered in the State, it would not be preempted by Federal law. We have also reviewed the May 6, 1988 letter from MEMA to Mr. Hiatt, in which MEMA discusses why it believes North Carolina's statute would not be preempted by Federal law. The MEMA discussion does not address the 'render inoperative' provision in section 108(a)(2)(A) of the Safety Act, which prohibits commercial businesses from adversely affecting the compliance of elements of design installed in a vehicle or item of equipment in compliance with a safety standard, regardless of whether the vehicle is new or used. As was previously stated, Federal law prohibits any manufacturer, dealer, distributor, or repair business from ever installing window tinting material for the owner of a car if the combination of the original glazing and the tinting material results in less than 70 percent light transmittance through any window of the car. To summarize, the North Carolina statute would be preempted to the extent that it seeks to permit some level of light transmittance other than that specified in Standard No. 205 for glazing in vehicles prior to the first purchase of the vehicles in good faith for purposes other than resale. Similarly, the statute would be preempted to the extent it seeks to permit the commercial installation of sunscreen materials with the result that the combination of the sunscreen material and the existing glazing no longer complies with the requirements of Standard No. 205. However, the North Carolina statute would not be preempted to the extent that it seeks to regulate the modifications that owners themselves can make to their vehicles or to the extent that it seeks to establish requirements for vehicles to be registered in the State, even if those requirements differ from those specified in Standard No. 205. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: 86-4.37OpenTYPE: INTERPRETATION-NHTSA DATE: 08/07/86 FROM: AUTHOR UNAVAILABLE; Erika Z. Jones; NHTSA TO: Larry H. McEntire -- Administrator, School Transportation, Florida Dept of Education TITLE: FMVSS INTERPRETATION TEXT:
Mr. Larry H McEntire Administrator, School Transportation Florida Department of Education Tallahassee, Florida 32301
I regret the delay in responding to your letter to this office asking whether certain "mini-vans" designed to carry a maximum of eight persons are classified by NHTSA as "passenger cars" or "multi-purpose passenger vehicles" (MPV's), for purposes of complying with the Federal motor vehicle safety standards.
I would like to begin by clarifying that the classification of a particular vehicle is determined in the first instance by its manufacturer, and not by NHTSA. Under our certification requirements, (49 CFR Part 567), manufacturers are required to specify the type of their vehicles in accordance with the definitions set forth in part 571.3 of our regulations and must certify that their motor vehicles comply with all the motor vehicle safety standards applicable to that type. We define an MPV in Part 571.3 as "a motor vehicle . . . designed to carry 10 persons or less which is constructed either on a truck chassis or with special features for occasional off-road operation."
Information we have received regarding manufacturer certification discloses that manufacturers classify cargo-carrying models of the Ford Aerostar, and G.M. Astro and Safari as "trucks". A "truck" is defined in Part 571.3 as "a motor vehicle . . . except a trailer, designed primarily for the transportation of property or special purpose equipment." We understand that passenger models of mini- vans designed to carry up to eight passengers utilize the same type of chassis used in truck models. It is likely, therefore, that the passenger model mini-vans you asked about would be classified by the "MVP" classification given by manufacturers to the Chrysler mini-van and Toyota Van.
On a related matter, you asked for our comments on your Department's recommendation to their school boards that they not condone parent's use of conventional vans (i.e., vans not meeting Federal or State school bus safety regulations) to transport school children to school-related events. Mr. Arnold Spencer of Rockledge, Florida, recently wrote to our office concerning the above recommendation and requested us to explain how our school bus regulations apply to persons owning vans. I have enclosed a copy of our April 25, 1986 response to Mr. Spencer which you might find helpful. I hope this information is helpful. If you have further questions, please feel free to contact us.
Sincerely,
Erika Z. Jones Chief Counsel
Enclosure
May 9, 1986
Mr. Frank Berndt Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, Southwest Washington, D.C. 20590
Dear Mr. Berndt:
I am writing in regards to an earlier letter written to you on December 9, 1985 requesting your assistance in clarifying whether mini-vans are defined as "passenger cars" or "multi-purpose vehicles".
Attached is a copy of the earlier correspondence for your information. Your earliest response would be appreciated. Sincerely,
Larry H. McEntire Administrator School Transportation
LHM/cs
attachment
December 9, 1985 Mr. Frank Berndt Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street, Southwest Washington, D.C. 20590
Dear Mr. Berndt:
Your assistance is needed in responding to a concern being expressed by various school districts in Florida.
Florida currently has a law, Section 234.051, Florida Statutes, which requires the local school districts to use school buses meeting all state and federal requirements for transporting children to school or school related activities. The same law also specifically exempts passenger cars from having to meet school bus specifications.
Based upon the above law, Florida does not permit local school boards to use conventional vans for transporting students. Only those units which have been converted to meet all federal and state school bus requirements and for which a letter of certification is on file from the manufacturer are permitted to be used by the school districts.
Lately, a number of school districts have inquired to the Department concerning the use of the new "mini-vans" for transporting students. Specifically, the Chrysler mini-vans, Ford Aerostar, General Motors Astro and Safari, Toyota Van and Volkswagon Vanagon which transport a maximum of eight people including the driver.
My specific request to you is how are these units defined under the federal definitions by the National Highway Traffic Safety Administration? Are they defined as "passenger cars" or "multi- purpose vehicles"?
Along these same lines, the Florida Department of Education has taken the position recommending to school boards that when parents volunteer to transport children to activities which are condoned, sponsored, or under the authority of the school board, they should not permit the transportation of these students in conventional vans. This position is based upon the fact these units do not meet school bus specifications or standards; are not specifically exempt as with passenger cars; and, the risk of liability to the school board becomes highly magnified.
Any comments you may provide regarding this position is also appreciated. Your assistance in addressing the above issues would be very helpful in my responding to the local school boards in Florida. Sincerely,
Larry H. McEntire Administrator School Transportation |
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ID: 2171yOpen The Honorable John D. Dingell Dear Mr. Chairman: Thank you for your letter of September 22, 1989, forwarding Representative Morella's letter inquiring about the requirements of Federal law and regulations as they apply to the tinting of motor vehicle windows for medical reasons. We recently began a rulemaking proceeding on the issue of tinting, and I welcome this opportunity to discuss the matter. The enclosures to Ms. Morella's letter described a case in which a person suffers from a skin disease called vitiligo and was advised to avoid exposure to the sun's rays. The presumption is that this person needs more protection from the sun than that afforded by vehicle windows that conform to the Federal standard. Federal Motor Vehicle Safety Standard No. 205, Glazing Materials, establishes a minimum 70 percent light transmissibility for glazing at levels "requisite for driving visibility," which includes all windows in passenger cars. When a requirement is established in a Federal safety standard, the National Traffic and Motor Vehicle Safety Act prohibits any person from manufacturing, selling, or importing a new vehicle that does not comply with that requirement. The Safety Act does not provide for individual medical exemptions. Similarly, the Safety Act prohibits any manufacturer, distributor, dealer, or repair business from "rendering inoperative" an element of design required by a safety standard, such as minimum light transmissibility. This "render inoperative" prohibition applies to vehicles after sale to purchasers. Neither this "render inoperative" provision nor any other Federal requirement would prohibit an individual vehicle owner from modifying their own vehicles, even if the modifications cause the vehicle to no longer comply with the Federal safety standards. Thus, an individual vehicle owner can make whatever modifications he or she likes, for medical or any other reasons, without violating Federal law. However, the individual States have the authority to regulate modifications that owners may make to their vehicles, and many States have chosen to regulate window tinting. For your reference, I have enclosed copies of our July 8, 1988 letter to Representative Shumway and our November 1, 1988 letter to Representative Byron on this subject. The minimum light transmissibility requirement in Standard No. 205 represents a balancing of legitimate competing interests. On the one hand, safety considerations dictate that drivers must be able to see and analyze the traffic situation in which the vehicle is being operated and react to that situation properly and promptly. To the extent that some of the available light is not transmitted through the vehicle glazing, the driver's ability to react to the traffic situation is potentially delayed. This is especially true under low light conditions, such as occur at night and on very overcast days. On the other hand, there are legitimate reasons for allowing some tinting of vehicle windows. These include avoiding excessive heat for all vehicle occupants, reducing glare for the driver, preserving the vehicle interior, and helping persons with medical conditions that are sensitive to the sun's rays. NHTSA balanced these competing interests by establishing the current 70 percent minimum light transmissibility requirement in Standard No. 205. However, the agency was asked in a petition for rulemaking to reexamine this balance and to permit darker tinting of windows, by lowering the minimum light transmissibility requirement. We decided to reexamine whether the current minimum light transmissibility requirement continues to represent the most appropriate and reasonable balance of the competing interests. Accordingly, on July 20, 1989, this agency published a request for comments on a comprehensive review of the 70 percent light transmissibility requirement for side and rear window glazing in passenger automobiles. One of the issues raised was the light transmissibility standard's effect on those who need more protection from the sun's ultraviolet rays. The comment period for this notice closed on September 18, 1989. The agency received nearly one hundred comments on this issue and is currently reviewing those comments. We will notify you and Ms. Morella when we announce our decision. I have placed a copy of your letter and this response in the public docket for this rulemaking action. I hope this information is helpful. Sincerely,
Jeffrey R. Miller Acting Administrator Enclosures cc: The Honorable Constance A. Morella ref:205 d:ll/20/89 |
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ID: nht76-2.12OpenDATE: 04/14/76 FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA TO: Blue Bird Body Company TITLE: FMVSS INTERPRETATION TEXT: This responds to Blue Bird Body Company's March 15, 1976, request for confirmation that calculation of the material tensile strength of body panels under S6.2(a) of Standard No. 221, School Bus Body Joint Strength, is based on the minimum thickness permitted by American Society for Testing and Materials (ASTM) Standard 525 for the thickness specified in ordering the material. This response also reflects the April 1, 1976, meeting held between Blue Bird representatives and National Highway Traffic Safety Administration (NHTSA) personnel at Department of Transportation headquarters. Under ASTM standards, the thickness of listed materials is permitted to vary from the specified or "nominal" thickness by a small amount. If the thickness tolerance of a material is specified by the ASTM, the NHTSA bases its determination of thickness on the "minimum thickness" specified for that material in the 1973 edition of the Annual Book of ASTM Standards. If the thickness tolerance of a material is not specified by the ASTM, the NHTSA uses the minimum thickness permitted by the school bus manufacturer's material specification. YOURS TRULY, BLUE BIRD BODY COMPANY March 15, 1976 Mr. Richard B. Dyson Assistant Chief Counsel National Highway Traffic Safety Administration SUBJECT: FMVSS 221 - SCHOOL BUS BODY JOINT STRENGTH In S6.2(a) the subject standard makes provision for the manufacturer to determine the material tensile strength as published by the ASTM. This information is required before a manufacturer can design body joints and tooling to manufacture those joints in compliance with the subject standard. Material tensile strength as published by the ASTM has a tolerance and we need to know to which end of the tolerance we must design. The standard adequately addresses this problem in S6.2(a) by stating ". . . .the relative tensile strength for such material is the minimum tensile strength specified for that material in the 1973 Edition of the Annual Book of ASTM Standards." This only addresses half of the tolerance problem. The ASTM standards show tolerances for metal thickness ranges. In the absence of specific guidelines of this problem and because we must commit for tooling immediately, we are using the minimum thickness based on our specified thickness and tolerance in ASTM A525-73. This approach seems to be justified in light of the tensile strength guidelines given in S6.2(a). If this approach is not satisfactory, please contact us by telephone immediately. We will also appreciate a written reply to this letter at your earliest convenience. W. G. Milby Staff Engineer cc: Bob Williams; Jim Moorman; Jim Swift |
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ID: aiam2358OpenMr. J. W. Lawrence, Manager, Safety and Environmental Engineering, White Motor Corporation, P.O. Box 91500, Cleveland, OH 44101; Mr. J. W. Lawrence Manager Safety and Environmental Engineering White Motor Corporation P.O. Box 91500 Cleveland OH 44101; Dear Mr. Lawrence: This responds to White Motor Corporation's April 26, 1976, questio whether S5.3.3 and S5.3.4 of Standard No. 121, *Air Brake Systems*, require minimum brake chamber air pressures of 60 psi and 95 psi, respectively, or whether these air pressures are included in the sections only as 'bench marks' on which to base specifications for minimum actuation and release timing in brake systems. Section S5.3.3 specifies in part:; >>>. . .With an initial service reservoir system air pressure of 10 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, reach 60 psi in not more than 0.45 seconds. . . .<<<; Your understanding that S5.3.3 and S5.3.4 only specify the ai pressures of 60 psi and 95 psi as the basis for timing requirements is correct. Neither value is intended as a requirement that the vehicle be designed to provide a certain level of brake chamber air pressure. The values were based on an understanding of the typical configuration of existing air brake systems at the time the final rule was issued.; In response to your request for interpretation of these sections i view of White's intent to use a lower air pressure than was commonly used in the past, the agency will utilize the stated 60-psi value or a value that is 70 percent of a maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower. In the case of release, the stated 95-psi value or the value that represents maximum air pressure (measured by the NHTSA at the brake chamber), whichever is lower, will be used. For purposes of this determination, the maximum air pressure in the brake chamber is that obtainable with full brake application when the pressure in the service reservoir is at 100 psi. Use of the maximum air pressure application timing would be unreasonable because of the decreased rate of air pressure build-up that occurs as the brake chambers reach maximum pressure.; The agency will issue an interpretive amendment to S5.3.3 and S5.3.4 t reflect this interpretation.; Sincerely, Frank Berndt, Acting Chief Counsel |
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.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.