ID: nht74-2.24

DATE: 07/03/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: White Motor Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your recent request for an interpretation of S5.3.1.2 of Standard No. 121, Air brake systems. That section permits certain vehicles to avoid the stopping distance requirement if their brakes conform to a retardation formula and values found in another section of the standard (S5.4.1).

The language of S5.3.1.2 makes clear that any truck in the described category need not meet the stopping distance requirements if its brakes satisfy the retardation formula and values of S5.4.1, and therefore none of the exceptions found in S5.4.1 apply to vehicles subject to the requirements of S5.3.1.2.

This interpretation also appears in the preamble to Notice 2 of Docket No. 73-10, and is enclosed for your information.

Yours truly,

ATTACH.

James B. Gregory, Administrator -- National Highway Traffic Safety Administration

Subject: Request for Interpretation of Standard 121, Docket 74-10; Notice 2, Section 5.3.1.2

Dear Dr. Gregory:

The amended standard, Section @ 5.3.1.2 states that a vehicle manufactured before September 1, 1975, that has a front steerable axle with a GAWR of 16,000 pounds or more, or a front steerable drive axle, need not meet the stopping distance requirement if its brakes conform to the retardation formula and values of @ 5.4.1 applied to the vehicle as a whole and to the front axle system separately.

However, Section @ 5.4.1 as now amended, applies only to "each vehicle designed to be towed by another vehicle equipped with air brakes" and, therefore, there are no retardation requirements applicable to either a towing vehicle or to a vehicle which is used by itself. Under the circumstances, it would appear that such vehicles would not be required to meet any specific retardation requirements.

We request an interpretation of the applicability of @ 5.4.1 to these special classes of vehicles for the interim period where no stopping distance requirements are in effect.

Sincerely, WHITE MOTOR CORPORATION; J. W. Lawrence -- Manager Safety and Environmental Engineering

ID: nht74-2.25

DATE: 05/10/74

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Kelsey-Hayes Company

TITLE: FMVSS INTERPRETATION

TEXT: This will acknowledge receipt of Kelsey-Hayes' petition to add "after-stop" to the description of temperature range in S6.1.8.1 of Standard No. 121 and S7.4.2.1.2 of Standard No. 105a.

The temperature range is in fact intended to describe the after stop temperature of the brakes, and the language of the sections will be clarified in the future.

Yours truly,

ATTACH.

April 25, 1974

U. S. Department of Transportation, National Highway Traffic Safety Administration,

Richard B. Dyson -- Assistant Chief Counsel

RE: Requests for Interpretation -- FMVSS 105 (9/1/75) S7.4.2.1.2; FMVSS 121 S6.1.8.1; Your file numbers N40-30 (ZTV) and (TWH); Brake Burnish Procedure

Dear Mr. Dyson:

You have responded to our requests for interpretation on identical language in these subsections of these standards and advised that the word maximum would be deleted in the sentence ending in ". . . maintain a maximum temperature of 500 degrees F +/- 50 degrees F."

We recommend one further clarification to eliminate ambiguity, namely, that the phrase "after-stop temperature" be added to the sentence, as follows:

"If during any of the brake applications specified in , the hottest brake reaches 500 degrees F, make the remainder of the 500 applications from that speed except that a higher or lower speed shall be used as necessary to maintain an after-stop temperature of 500 degrees F +/- 50 degrees F."

We further suggest that a notice be issued proposing this clarification.

Very truly yours,

John F. McCuen -- Attorney, KELSEY-HAYES COMPANY

cc: W. T. Birge; D. Renner

ID: nht74-2.26

DATE: 07/09/74

FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA

TO: Wanger Electric Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your March 12, 1974, request for interpretation of the volume requirements for service brake chambers in S5.1.2.1 and S5.2.1.2 of Standard No. 121, Air Brake Systems:

S5.1.2 Total service reservoir volume shall be at least eight times the combined volume of all service brake chambers at maximum travel of the pistons or diaphragms.

You also requested the addition of language equating brake chamber volume with brake chamber displacement, based on nominal effective area and rated stroke.

In testing for compliance with S5.1.2.1 and S5.2.1.2, the NHTSA will accept a manufacturer's published "rated volume" of the brake chamber with the piston or diaphragm at maximum travel. This means that the manufacturer may specify the full stroke of the piston or diaphragm and compute the "rated volume" based on the designed volume of the chamber and the full stroke he has established. This volume may be somewhat larger than "nominal brake chamber displacement" which does not necessarily account for the void ahead of the relaxed diaphragm or piston, the so-called "pre-fill volume". This volume must be included because it must be pressurized along with the displaced volume.

In the absence of manufacturer's published ratings, the NHTSA will measure the brake chamber volume with the push rod at maximum stroke.

Your request to add explanatory language to the standard of the measurement technique is denied as unnecessary in view of this interpretation.

Sincerely,

ATTACH.

March 12, 1974

James B. Gregory, Administrator -- National Highway Traffic Safety Administration

Re: Docket 73-13; Notice 3 74-10; Notice 1 49 CFR 571.121

Petition for Reconsideration FMVSS-121, Air Brake Systems

Dear Dr. Gregory:

We were pleased to note in the March 1, 1974, Federal Register (39FR-7966) that the NHTSA needed further consideration on petitions for air tank volume before an answer would be published.

We apparently did not place adequate emphasis on this facet of FMVSS-121 compliance. Instead of a petition, we addressed a letter dated July 13, 1973, to the Director, Office of Operating Systems, for an interpretation. In that letter we asked only one question and it is quoted below:

Will the NHTSA accept the vehicle or chamber manufacturers' nominal value for maximum allowable stroke on each actuator when determining the minimum vehicle reservoir capacity required by S5.1.2.1 and S5.2.1.2?

In view of the absence of any response to a fundamental question, the manufacturers of air-braked vehicles and air brake equipment have gone in divergent directions with their own "interpretations." Apparently, it is a more profound problem than we or our competitors anticipated. In defense of our commercial position in this product area, we now find it necessary to submit this letter as a Petition.

Petition (1) We petition for an answer to the question posed in our July 13, 1973, letter (as quoted above).

In support of this petition we have attached a copy of that letter as Appendix A. The unanswered question appears on Page 4.

We will risk being a little repetitious, but our concern is that too much emphasis is being placed on finite measurements of chamber volume and reservoir volumes. From a statistical viewpoint, the case of trailer reservoir volume is a classic example of compliance or certification "overkill." S5.2.1.2 reads:

S5.2.1.2 Total reservoir volume shall be at least eight times the combined volume of all service brake chambers at maximum travel of the pistons or diaphragms.

In mathematical terms the word "eight" has a numerical equivalent of 8. For degrees of accuracy it could be 8.0, 8.00, 8.000, --- but it was just commonplace old "number eight."

In our letter of July 13, 1973, we reproduced the SAE J813 Recommended Practice for Air Brake Reservoir Volume (see Page 2, Appendix A). A truck trailer was considered to need "not less than 4 times the actuator displacement volume at maximum travel of the piston or diaphragm." The industry has accepted this 100% improvement in stored volume. Now all we are trying to do is determine whether this gross volume can be determined by simple mathematics or will require ultra-sensitive physical measurement of the actuators and the associated reservoirs.

Not only do the simple calculations benefit the designers of vehicles and brake systems, they have an obvious benefit to the NHTSA Office of Standards Enforcement.

Does the Office of Operating Systems assign the accuracy of these measurements to four significant figures necessary to the safe operation of a trailer? We see no technical justification for this. If there is, then it should be public knowledge. This is our rationale. Again using the most popular trailer as the example: It has 2 cam brakes with type 30 (30 square inch nominal effective area) chambers for actuation. These chambers have a nominal stroke of 2 1/2 in. (one source has a 2 3/4 inch stroke).

Under SAE J813 the required reservoir volume is:

4 x (Nominal Area) x (Nominal Max. Stroke) x (No. of Chambers) = Volume or 4 (30) (2.5) (2) = 600 cubic inches.

Under S5.2.1.2 of FMVSS the simple approach is

8 (30) (2.5) (2) = 1200 cubic inches.

Now we industry specialists get concerned by public statements at NHTSA meetings that it should be easy to measure --- put it (chamber) on a table, stroke it under pressure and measure the volume.

Production tolerances may allow a maximum stroke to extend to 2.65 inches or another 8 (30) (0.15) (2) = 25 cubic inches.

A further study points out that chambers have a void ahead of the relaxed diaphragm. It is there to assure good entry of unrestricted air flow to the effective area. This pre-fill volume can be at least 5 cubic inches per chamber or (8) (5) (2) = 80 cubic inches per axle.

At full stroke the defection of the non-rigid diaphragm adds another approximate 12 cubic inches per chamber or 8 (12) (2) = 192 cubic inches per axle. It is not needed at mid-stroke. Therefore, this is a superfluous requirement. There are many other more significant factors affecting chamber/brake output if we consider brake effectiveness under such an extreme condition.

The gross addition for these three factors alone is -

25 cu. inches 80 cu. inches +192 cu. inches

297 cubic inches per axle.

Note 192 cubic inches is beyond the point of useful volume and should not be a part of this measurement anyway.

To prove compliance or non-compliance using all of the added factors would require a very sophisticated laboratory contract and allied equipment. The report would be documented by instrument calibrations and certifications traced back to the National Bureau of Standards.

Did the NHTSA really want its "doctrine of adversity" to become this costly a situation? We can't believe the task force responsible for the first issue of FMVSS-121 was that conversant with the detailed construction of chambers to recognize the disparity of viewpoints in measuring technique that have evolved. We are certain there was not one iota of data in the DOT contract files to substantiate this stringent a need. From the public meetings we recall that concern for reservoir size was subordinated in seriousness because trailers are thought to have all sorts of space for reservoirs. In some cases this is true. However, random tank placement is not possible. One other FMVSS-121 requirement makes remote tank locations impractical.

That requirement is the Brake Actuation Time found in S5.3.3. To reach 60 psi in 0.25 sec. from actuation of the test rig control requires optimum system designing --- this prohibits such luxuries as -

(a) long air lines to the chambers

(b) untested hose sizes for these line

(c) remote reservoirs to contain this superfluous volume of air.

We could not predict how essential all of this would be in 1971, but we have come a long way. It was late Spring, 1973, when we became extremely concerned about contract testing to evaluate reservoir volume. We had already acknowledged that we were part of a regulated industry. On July 13, 1973, we demonstrated our intent to act like we were being regulated and posed our "simple" question. We are disappointed that an early response was impossible to develop and furnish. We are further disappointed that the 1972 and 1973 petitions filed by a competitor on this same subject matter have not resulted in positive rulemaking actions to resolve the internal problems that must exist between the Office of Operating Systems and Office of Standards Enforcement.

Perhaps this aspect of FMVSS-121 is not as vital as decisions on the effective date, but rule content does influence ability to meet effective dates. We trust this reinforcement of open petitions will prompt immediate action.

In summary, we believe an affirmative reply to our July 13, 1973, question will not adversely affect vehicle safety. If there is any suspicion in the Office of Standards Enforcement that the vehicle manufacturers or chamber manufacturers would falsify their nominal stroke or nominal areas for these components to avoid "proper" sizing of reservoirs, then that should be a subject for docket comment. We are already charged with honest manufacturing recommendations for brake adjustment, air compressor capacity, interpretation of "controlled lockup," option choices for parking brake mode, transmission gear range, tire inflation pressure, gross vehicle weight rating, gross axle weight ratings, burnish options and others not mentioned.

Our conclusion is that the following petition will reflect a simple means for calculations:

Petition (2) We petition for the addition of this sentence to S5.2.1.2 (see Page 2): "For purposes of establishing reservoir volumes, brake chamber displacement is equal to the product of the nominal effective area and nominal rated stroke."

It may be that the relative ease of chamber and reservoir measurements makes them good "compliance targets," but if the enforcement of FMVSS-121 is reduced to such attack, the goal of the NHTSA and the efforts of the industry to attain these goals will be unjustly inhibited in future vehicle safety programs.

Very cordially yours,

WAGNER ELECTRIC CORPORATION; John W. Kourik -- Chief Engineer, Automotive Products

Attachment: Appendix A

WAGNER ELECTRIC CORPORATION WAGNER DIVISION

July 13, 1973

Elwood T. Driver, Code 41-30 -- Director, Office of Operating Systems, NHTSA

Gentlemen:

As a manufacturer of brakes and air brake actuating system components, Wagner Electric Corporation is desirous of consistent and accurate interpretations of all applicable Federal Motor Vehicle Safety Standards. We are encountering an increasing amount of confusion in the industry regarding the method or procedure to be used in establishing the air reservoir capacity for air brake vehicles as required by FMVSS-121 (Section 5.1.2.1 and Section 5.2.1.2). We are, therefore, requesting interpretation and/or clarification of these sections with regard to the wording ". . . the combined volume of all service brake chambers at maximum travel of the pistons or diaphragms . . ." as found in Sections 5.1.2.1 and 5.2.1.2.

While the method of measurement of brake actuator volume may seem insignificant, in some cases it has become a major concern to decide whether an existing reservoir volume can be used or whether a new air reservoir must be made up with a slightly larger capacity. The determining factor is how the brake actuator volume requirements are measured. Therefore, a prompt response would be most appreciated so that the design and specification of air system components required to meet FMVSS-121 can be finalized.

Prior to Docket 70-17 and Docket 70-16 work by the NHTSA the recommendation for air brake reservoir volume used by some of the vehicle manufacturers was SAE J813.

AIR BRAKE RESERVOIR VOLUME

AIR BRAKE RESERVOIR VOLUME -- SAE J813

SAE Recommended Practice

Report of Brake Committee approved November 1961

Scope -- This recommended practice establishes minimum volume requirements for air reservoirs for automotive vehicles using compressed air systems essentially for the actuation of the brake. Accessories that utilize compressed air for their operation are not included in the conventional air brake system and, therefore, additional volume must be provided for their requirements. Where air operated accessories are used, a check valve or equivalent device will be required to provide protection to the brake system.

These recommendations for minimum reservoir volumes in air brake systems are based on past experience and are intended as a guide in selecting the proper size reservoirs to assure an adequate source of braking power under normal level operating conditions.

General -- The volume of the brake actuators in the air brake system, commonly referred to as brake cylinders, brake chambers, or roto-chambers, varies with the diameter and travel of the piston or diaphragm. The reservoir volume depends upon the size and number of the actuators on the vehicle and the type of vehicle service. Recommended volumes are calculated in Table 1 by multiplying the total volume of all actuators by an experience factor. Depending on traffic conditions and terrain, reservoir volumes, greater than the minimum values, should be considered.

(Illegible Table)

This recommended practice had also been endorsed in the Final Report of the Consolidated Brake Task Force of the Joint AMA-TIMA Brake Committee dated October 28, 1965. SAE J813 was reproduced above to simplify the evaluation of the comments which follow for those individuals who were not acquainted with previous (and current) recommended practice. Note that trucks or truck-tractors required only eight (8) times the actuator displacement volume and truck-trailers only four (4) times the actuator volume. We know from our experience that the maximum travel used throughout the industry in determining actuator displacement was the nominal value for the stroke of the actuator and that there was no attempt to incorporate production variations due to manufacturing tolerances. When we compare the values for the volume in J813 with the requirements of S5.1.2.1 (trucks and buses) and S5.2.1.2 (trailers) it will be noted that significant improvement in the stored air volume has been made mandatory by FMVSS-121. There is even further significance in this change to the large volume requirement in that many vehicles were built and are being built in 1973 with reservoir capacities less than the requirements specified in J813.

Perhaps it was not recognized at the time that FMVSS-121 issued that the efficiency of brake chambers has the characteristic shown in Figure 2. The performance requirements of FMVSS-121 for (1) actual stopping distance measurements and (2) timing requirements are based on brakes being adjusted to the vehicle manufacturers' recommendation. Figure 2 demonstrates that the mid stroke of most brake chambers is the point of approximate 100% efficiency. Shorter strokes are associated with higher output than would be nominally expected. In S5.1.2.1 and S5.2.1.2 the volume of all service reservoirs and supply reservoirs is based on ". . . the combined volume of all service brake chambers at maximum travel of pistons or diaphragms." As vehicle manufacturers begin to finalize the design of the variety of systems essential to the different vehicle chassis, space for air reservoirs is precious. It is advantageous for the vehicle manufacturers and the component suppliers to select a limited number of reservoir sizes for the purposes of simplicity in design, ease of procurement, and economy of using a few standard reservoir sizes.

If the most adverse characteristics are to be determined for compliance, not only must the chambers be subjected to extremely close measurement of displacement but the net displacement of air reservoirs must be measured very precisely. We believe it is advantageous for the NHTSA to recognize that the twelve (12) and eight (8) times minimum volume requirement for trucks and trailers respectively does not require the same degree of accuracy needed to measure application and release times or to measure stopping distance compliance. We are therefore proposing that chamber strokes used in these calculations be based on the nominal values established as the maximum allowable stroke for the components installed on the vehicle. It will be noted in Figure 1 that the probable variation between a nominal stroke of 2.50" and a stroke which allows for all production tolerances is only 97.1-90.0 = 7.1 cubic inches per chamber. On a tandem axle trailer or a tandem drive axle tractor this 28 cubic inch variation has been noted to warrant an increase in the number of reservoirs essential for very precise compliance to the general requirement in Sections 5.1.2.1 and 5.2.1.2. This seems to be an unnecessary expense for the manufacturers to incur since standard reservoir volumes could be used at the lower value without any real sacrifice in vehicle performance. The slight variation in stored volume will not have any adverse effect on application time. If it did, then correction in the volume would have to be necessary in order to comply with the application time requirements for a given vehicle. We do not see that this slight volumetric difference is essential for skid control systems. It is characteristic of skid control systems to exhaust air from the service line and deplete the service reservoir(s). When skid control is functioning the performance of any system becomes self-limiting at a point at which the air pressure no longer produces sufficient brake torque to generate impending skids. Once this pressure level is achieved there is no further demand for reserve capacity in the air brake system. Therefore the stopping requirements for vehicles from 60 and 20 mph can be satisfied in the road test phase of FMVSS-121 without having to be too precise in establishing the actual net chamber/reservoir measurements.

Typical of some of the problems which can be generated by the preciseness of FMVSS-121 is the Figure 1 test rig for trailers. While 2000 cubic inch reservoirs could be obtained or could be made by modification of standard reservoir sizes, the typical unit produced in the industry is 2020 cubic inches. By using inert ballast material, a reduction of 20 cubic inches in the stored capacity of the reservoir is relatively easy. This is a case where we do not feel that a 20 cubic inch variation is really a significant part of the over-all performance requirement of either the vehicle or the test rig but the strict implementation of Figure 1 requires special equipment and added expense.

We have presented this appraisal of the situation which confronts the vendor and vehicle industry in order to provide some relief that will be of mutual benefit to the public, the vehicle manufacturers, and the NHTSA by concentrating on the critical aspects of FMVSS-121. If each phase of the Standard is put into its proper perspective it will enable the NHTSA and the industry to begin implementation of good cost/benefit practices. For this reason (Illegible Word) then ask the following:

Will the NHTSA accept the vehicle or chamber manufacturers' nominal value for maximum allowable stroke on each actuator when determining the minimum vehicle reservoir capacity required by S5.1.2.1 and S5.2.1.2?

For minor clarification, this question is directed at using (1) the middle of the three curves shown on Figure 1; (volume versus stroke at 100 psi) and (2) a volumetric requirement of 90 cubic inches at a nominal stroke of 2.50". We have encircled that point for emphasis.

Very truly yours,

John W. Kourik -- Chief Engineer, Automotive Products

Attach. Figures 1 & 2 (Graphics omitted)

ID: nht79-4.10

DATE: 03/13/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your February 1, 1979, letter asking whether any law or regulation prohibits the remanufacture of a school bus with an old chassis and a new body when the completed vehicle does not comply with the new safety standards.

As you are aware, the agency has stated many times that such a remanufactured vehicle need only comply with the standards in effect on the date of manufacture of the chassis as long as the remanufacturing process conforms to the guidelines established in Part 571.7(e) of our regulations. The agency does not view the remanufacturing problem as significant, because a vehicle's chassis normally wears out before its body. The recycling of noncomplying buses will cease when the supply of used chassis manufactured prior to April 1, 1977, disappears.

SINCERELY,

BLUE BIRD BODY COMPANY

February 1, 1979

Joseph J. Levin, Jr. Chief Counsel National Highway Traffic Safety Administration

Dear Mr. Levin:

The intent of Public Law 93-492, Motor Vehicle and School Bus Safety Amendments of 1974, and the subsequent regulations resulting from that law was to upgrade the safety of the national school bus fleet.

We have recently become aware of an industry which seems to be designed to circumvent the intent of public law 93-492. The industry (see enclosure) is involved in the restoration and remanufacture of complete school buses including body and chassis.

We are aware of the agency's recent interpretation regarding the manufacture of bodies stating that the bodies must meet the safety standards that were in effect on the date of manufacture of the chassis.

However, we feel that this new industry could indefinitely recycle old buses into the fleet which do not meet the congressionally mandated safety standards for school buses.

In our opinion, we feel that this is a flagrant violation of the intent of the law. Therefore, we would like to ask you if there are any regulations or laws which would prohibit this practice.

Thank you for your early reply.

W. G. Milby Manager, Engineering Services

School Bus Restoration Co.

511 SO. LINCOLN STREET ELKHORN. WISCONSIN 53121 (414) 723-4309

PRICE LIST

EFFECTIVE AUGUST 1, 1978

School Bus Standard Type Forward Engine Cowl Mounted Specification 105

All body types, all lengths up thru 66 pass - Chevrolet Chassis $ 8950 *

All body types, all lengths up thru 66 pass - Ford Chassis $ 9250 *

All body types, all lengths up thru 66 pass - International Chassis $ 9250 *

All body types, all lengths up thru 66 pass - Dodge Chassis $ 8950 *

All body types, all lengths up thru 66 pass - G.M.C. Chassis $ 8950 *

Busses equipped with power steering additional 32500 *

* All Prices Plus Factory Rebult. Or New Engines. (Your Option)

Busses equipped with automatic transmission. Special Quote

School Bus Body Only

All body types, all lengths 48 thru 66 pass - Any Chassis 580000

Add-On eight light warning system 400

Please Add 20000 for each additional row of seats - Bus size over 66 pass. Restoration of internally mounted front engine and rear engine busses - will be on Special Quotation.

Any bus bearing unusual wear or damage will be on Special Quotation. All work performed is Guaranteed for 6 months or 6,000 miles. Guarantees on tires and batteries will be limited to mfg. Guarantee.

Engines are Guaranteed by the engine manufacturer in accordance with their individual policy and not by SCHOOL BUS RESTORATION. Or it's contract manufacturers.

All prices are subject to change without notice.

ID: nht79-4.11

DATE: 09/06/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: MMC Services Inc.

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your recent letter requesting an interpretation concerning the proper "designated seating capacity" for the "Dodge D-50" and "Plymouth Arrow" pick-up trucks. The trucks with which you are concerned have bench seats with 53.5 inches of hip room, with a contoured indentation at the center position for the gear shift lever. You believe that only two positions should be designed for this type bench seat.

As stated in the preamble to the recent notice amending the definition of "designated seating position", and noted in your letter, the presence of a floor gear-shift lever would not normally be sufficient to discourage or make use of a center position on a large bench seat impossible, even if the bench seat has a slightly indented contour for the shift lever (44 FR 23232, April 19, 1979). The notice did state that there could conceivably be a vehicle design in which the gear-shift lever would constitute an impediment to sitting. For example, if the lever extended to within a few inches of the seat back, the center position could not easily be used. This does not appear to be the case with the "Dodge D-50" or "Plymouth Arrow", however.

Since the bench seats in the subject vehicles have 53.5 inches of hip room, well over the 50-inch caveat in the amended definition, it is the agency's opinion that there should be three designated seating positions. The photographs enclosed in your letter show that three test dummies can be placed on the bench seat, even though somewhat crowded. Moreover, these photographs show two 95th-percentile male dummies and one 5th-percentile female dummy. If two (or three) 5th-percentile female dummies had been used in your demonstration, instead, you would have illustrated that there is more than ample room for three passengers to sit comfortably on a 53.5-inch bench seat. Also, human beings obviously have more flexibility than the stiff test dummies used in your demonstration. We believe that if you use human subjects in this same experiment (a 95th-percentile male driver and two 5th-percentile female passengers, for example), you will see that three persons can easily and comfortably occupy these bench seats.

Finally, I would emphasize that this letter only represents the agency's opinion based on the information supplied in your letter. The NHTSA does not pass approval on any vehicle design, for any safety standards, prior to the actual events that underlie certification. It is up to the manufacturer to determine whether its vehicles comply with all applicable safety standards and regulations, and to certify its vehicles in accordance with that determination.

SINCERELY,

MMC SERVICES INC. July 12, 1979

Office of Chief Counsel National Highway Traffic Safety Administration

Subject: Request for Interpretation of "Designated Seating Position" on small pickup truck

Dear Sir:

MMC Services Inc., on behalf of Mitsubishi Motors corporation, would like to have your official interpretation as to "Designated Seating Position" on the small pickup truck, which Mitsubishi Motors corporation has been manufacturing and which has been sold with the name of "Dodge D-50" and "Plymouth Arrow" in U.S.A. marketed by Chrysler corporation. Each one is a derivative from a basic small pickup truck and the dimentions of both trucks are absolutely same.

The bench seat in the pickup truck was originally designed for two persons by the manufacturer and the pickup truck is equipped with a floor gear-shift lever just in front of the seat which has a indented contour for the shift lever.

In the Federal Register/Vol. 44, No. 77/ Thursday, April 19, 1979 "Designated Seating Position" which is applicable from September 1, 1980 is defined as:

"----. Any bench or split-bench seat in a passenger car, truck or multipurpose passenger vehicle with a GVWR less than 10,000 pounds, having greater than 50 inches of hip room shall have not less than three designated seating positions, unless the seat design or vehicle design is such that the center position cannot be used for seating."

And there is a description in the same Federal Register as:

"--- the presence of a floor gear-shift lever would not normally be sufficient to discourage or make use of a center position or a bench seat impossible, even if the bench seat has a slightly indented contour for the shift lever."

According to the two descriptions relating the standard quoted above, the bench seat therefore seems to be for three persons.

However the bench seat on the D50 and Arrow pickup trucks is very uncomfortable with three people. This is evident when considering the position of the floor gear-shift lever. This gear-shift lever provide an impediment to the third person seated in the middle of the bench seat.

NHTSA interpretation is therefore requested as to whether or not the bench seat should not be designated for two persons.

As the data for your interpretation, we attach illustration (Fig. 1), pictures (Fig. 2 (A), (B), (C), (D) ) and sales catalogues for the pickup trucks.

We would appreciate your interpretation of this matter at your earliest convenience.

T. SHIMADA for T. Ohinouye President

cc: GUY HUNTER--OFC. OF VEHICLE SAFETY STANDARDS, NHTSA Enclosures omitted

ID: nht79-4.12

DATE: 06/21/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Macdonald Equipment Company

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your January 2, 1979, letter asking whether it is permissible to mount a snow plow on a vehicle when the weight of the snow plow will cause the vehicle to exceed its gross axle weight rating (GAWR). The answer to your question is no.

The GAWR of a vehicle is determined and established by a vehicle's manufacturer and represents a manufacturer's assessment of the maximum weight that each axle can safely sustain. When this weight rating is exceeded by the addition of equipment to a vehicle, the safety of a vehicle is jeopardized. Over a period of time, the excessive weight borne by the axle could result in unusual wear and eventual failure of the axle.

The National Highway Traffic Safety Administration requires manufacturers to label their vehicles with GAWR's to avoid the overload problem that you mention in your letter. The NHTSA has not granted exceptions from this requirement for snow plows. If you mount a snow plow on a new vehicle prior to first purchase, you must be sure that the vehicle continues to comply with all Federal safety standards and regulations. If the weight of the plow exceeds the GAWR of the vehicle, the vehicle would no longer comply with the certification regulation and would not comply with Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars. Further, the compliance of other safety standards could be impacted by the addition of that weight.

In the case of used vehicles on which you mount a snow plow, a manufacturer, repair business, distributor, or dealer may not knowingly render inoperative the compliance of a vehicle with the safety standards. The attachment of a snow plow that exceeds the gross axle weight rating would render inoperative the compliance of the vehicle with Standard No. 120. Accordingly, whether a vehicle is new or used, the additional weight of a snow plow that would exceed the GAWR of a vehicle would not be permissible.

The NHTSA understands the budgetary constraints of municipalities. However, financial considerations must be balanced against the potential loss of life that can occur when vehicles are routinely overloaded. Accordingly, vehicles that have snow plows or other devices mounted on them should have sufficient GAWR's to carry their intended load.

Sincerely,

Macdonald Equipment Company

January 2, 1979

Office of the Chief Counsel National Highway Traffic Safety Administration

Gentlemen:

We have talked with your people here in Denver as well as with Mr. Elliot in Washington concerning the mounting of snow plows on trucks and they recommended that we contact your office for an opinion.

We are a disbributor for both a snow plow manufacturer and for a snow plow truck manufacturer and in the course of business we have noticed a trend develop, which we feel needs some clarification. In recent years cities, counties and states agencies responsible for snow removal seem to be purchasing trucks with smaller front axle capacity ratings. This is the result of increased prices on trucks in recent years and the need of these agencies to stay within their budgets.

The result of this trend is that the front axle capacities of these smaller trucks will not allow us to mount a hitch and snow plow on the truck without overloading the front axle or severly limiting the Dump Body capacity to avoid overloading the front axle, which limits the units role in spreading sand on the icy roads.

We would like to know if the weight of the snow plow and hitch must be included when determining the weight on the front axle or if ther is some type of exemption for snow plows. Since snow removal is a necessity in much of our country during the winters and the snow plows are generally on the trucks only in the event of storm it would seem that if there is not an exemption for the snow plows at present, it is an area that some type arrangement needs to be worked out. If the trend to the smaller type trucks with front axles rated at 12,000 pound or less capacity continues and we feel it will, it will be impossible to mount snow plows on most trucks used by these agencies.

Since we feel that we are getting into a situation where front axle load is becoming a question, we would very much appreciate any information or instructions you can give us in this matter. If we can supply you with any further material we would be most happy to do so. Thank you.

Macdonald Equipment Company A. M. Dahm, President

ID: nht79-4.13

DATE: 07/17/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Department of Education; Ohio

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your June 15, 1979, letter asking about the use of standard production vans for the transportation of school children to or from school or related events. In particular, you ask whether a 15-passenger Dodge Maxi-Van can be used for school transportation.

Whether a new vehicle sold for use as a school vehicle must comply with the Federal school bus safety standards depends on whether the vehicle meets our definition of a bus. Our definition provides that a bus is "a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons." (Title 49 of the Code of Federal Regulations, Part 571.3). Thus, a vehicle that transport 10 or fewer persons may be sold as a school vehicle and need not comply with the Federal school bus safety standards. However, a Dodge Maxi-Van capable of carrying 15 persons is a bus. If such a vehicle is sold new for use as a school vehicle, it must comply with those standards.

ID: nht79-4.14

DATE: 06/15/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Subaru of America Inc.

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of May 23, 1979, addressed to Ms. Eileen T. Leahy of my staff, in which you provide further information in support of your earlier request for this agency's opinion as to whether a 1980 4WD Hatchback Sedan to be imported by Subaru of America can be classified as a multi-purpose passenger vehicle (MPV).

As I stated to you in my letter of May 31, 1979, the fact that a vehicle is equipped with four-wheel drive is not, in itself, sufficient to qualify the vehicle as an MPV, as that term is defined in 49 CFR @ 571.3. Your second letter lists six other features of the 1980 hatchback sedan which you state are designed to permit occasional off-road use. The additional features you describe are: a ground clearance of 8.07 inches, or 1.57 inches higher than a similar 2WD vehicle; adjusting devices to permit an additional 0.78 inches of ground clearance front and rear; an engine under-cover to protect the engine from rocks and other debris; a clutch cover to prevent entry of dust and sand; bumper overriders to protect front and rear bumpers; and a tubular guard in front of the air dam for protection from rocks and other debris.

The ground clearance you describe exceeds that specified in the definition of automobiles "capable of off-highway operation" contained in the fuel economy regulations (49 CFR @ 523.5 (b)(2)(iv)). In addition, the other features you describe appear to be designed to protect various parts of the vehicle from damage from rocks, sand and other types of debris that are more likely to be encountered in off-road driving. Therefore, all of the items you mention can be considered "'special features for occasional off-road operation" when determining the proper classification of the vehicle for purposes of compliance with Federal Motor Vehicle Safety Standards.

Since the vehicle as you have described it in your letters has several features in addition to four-wheel drive that make it suitable for occasional off-road use, it is the agency's opinion that the 4WD Hatchback Sedan would qualify as a multipurpose passenger vehicle.

SINCERELY,

May 23, 1979

Eileen Leahy Office of Chief Counsel U.S. Dept. of Transportation National Highway Traffic Safety Adm.

Re: 1980 4WD HB Sedan MPV

Dear Ms. Leahy: On April 23rd, our letter No. 056-79C requested your office's opinion regarding MPV classification of this carline. Based upon our recent telephone conversation, we provide the following list of special features, which in addition to four-wheel drive, will permit this vehicle to be operated for occasional off-road use.

1. The ground clearance is 8.07 inches which is 1.57 inches higher than a similar 2WD vehicle.

2. It is equipped with adjusting device(s) to further increase the ground clearance, both front and rear by an additional 0.78 inches.

3. An engine undercover is installed to protect the engine from rocks and other debris.

4. A special clutch cover is provided to prevent the invasion of dust and sand.

5. Bumper overriders are provided on front and rear bumpers to protect bumpers.

6. A tubular guard is placed in front of the air dam for protection from rocks and other debris.

Should you have any questions, please contact this office.

John Cordner Technical Assistant Product Compliance

ID: nht79-4.15

DATE: 03/07/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Truck Trailer Manufacturers Association

TITLE: FMVSR INTERPRETATION

TEXT: We regret the delay in responding to your April 18, 1978, letter criticizing the National Highway Traffic Safety Administration's (NHTSA) interpretation concerning the responsibility of a manufacturer for ensuring that its vehicles will not be overloaded when transporting materials for which they are designed. In that interpretation, the agency indicated that a vehicle whose tank cargo volume is of such size that it misrepresents the assigned GVWR and GAWR values of that vehicle, thus, inviting overloading might be considered to have a safety related defect. Please permit me to qualify the interpretation in the light of your criticism.

The NHTSA realizes that overloading is a problem created for the most part by the operator of a vehicle. Accordingly, it is not intended by the agency's interpretation or regulations to hold a vehicle manufacturer responsible for every situation in which a vehicle is overloaded. Most any type truck can be overloaded by the user. An operator should be aware of this possibility, however, given the amount of space on that vehicle on which cargo can be loaded and the broad range of cargo that can be transported by that vehicle. If a truck designed for the transportation of one specific cargo were misused by the operator to transport another type of cargo not intended by the vehicle manufacturer, then any resultant overloading would be the responsibility of the operator not of the manufacturer. However, when a vehicle designed to transport a specific cargo can be overloaded when filled to its capacity with that cargo, the NHTSA has determined this to be a problem created by the vehicle manufacturer and would consider taking action against a manufacturer to correct the problem. This agency's interpretation that a vehicle be able to safely transport its intended design cargo when fully loaded is an objective and unambiguous requirement and simply places the burden upon a manufacturer to ensure that the design cargo does not exceed the GAWR and GVWR.

Specifically we are concerned that a tank of fixed volumetric capacity could be loaded to exceed the vehicle's GAWR and GVWR values when filled with a commodity of design density simply because of the tank being too large.

When there is reason to believe that the density of a cargo likely to be transported could present a vehicle overloading problem, the manufacturer has a duty to provide a warning and information as a precaution in averting the potential hazard. The NHTSA does not object to the practice of partial loading of tankers and tank compartments for remaining within safe loading limits provided guidelines are furnished by manufacturers for performing approved loading operations. Prescribed precautions hopefully will counteract any tendency to perceive volume as the load limiting criterion. We would agree that loading information as contained in your enclosure would be a satisfactory means of conveying safety information and could be referenced on a conspicuous vehicle label.

SINCERELY,

Truck Trailer Manufacturers Association

April 18, 1978

Joseph J.-Levin, Jr. Chief Counsel Department of Transportation National Highway Traffic Safety Administration

Gentlemen:

This is a response to your letter of July 1, 1977, your file No. NOA-30, written to Mr. Jerry McNeil of American Trailers (ref. other correspondence on the same subject), regarding the act of a user's exceeding a vehicle's GVWR possibly being considered a safety defect.

We take strong exception to this interpretation for several reasons:

(1) Your interpretation assumes a user to be either not knowledgeable or dishonest by overloading a tank with a commodity with too high a density for the tanks total capacity. We must design with the premise that a user is knowledgeable and honest.

(2) Your interpretation excuses overloading of certain types of vehicles but not volumetric type. Whereas overloading is the responsibility of the user, any type vehicle can be intentionally or naively overloaded.

(3) Your interpretation, if strictly enforced, would eliminate the use of one vehicle for more than one density commodity at great expense to the consumer. However, all State and Federal weight laws are written using weight in pounds; there is no reference to density.

(4) Your interpretation is so general that it defies any definitive objective evaluation. It would be impossible to clearly define literally the thousands of load types or combinations of load types that are possible. Your interpretation would hold one party responsible for another party's violation of the law. We doubt that this would hold up in court.

Partial loading of tank vehicles has been a general practice of our industry for over 50 years.

It is done safely and for good reason.

The most common example of partially loaded tanks is the typical 9000 gallon aluminum gasoline tank with 5 compartments. The tank weighs approximately 10,000 pounds and the typical GVWR of a vehicle such as this would be 70,000 lbs. Full loading with gasoline at 6.1 lb./gallon would provide a gross vehicle weight of 64,900 pounds (54,900 lb. of product & 10,000 lb. of tank), well within the vehicle's GVWR.

Partial loading with home heating oil at 7.2 lbs/gallon is achieved by leaving the third tank compartment empty (see attached sketch), reducing the total volume capacity to 7625 gallons and maintaining a gross vehicle weight of 64,900 lbs. - again 54,900 lb. product, 10,000 lbs. of tank.

This double purpose tank is versatile, practical, safe and very common. We estimate the total fleet of 9000 gallons tank to be about 3000 units. There are also many more gasoline tank both larger and smaller than 9000 gallons.

If we understand you correctly, your interpretation is that if an operator loads home heating oil into all five compartments overloading the vehicle and exceeding the gross vehicle rate rating (GVWR), the manufacturer may be held liable for a safety defect and be subject to a recall campaign. If, however, an operator loads a flatbed or van trailer with automobile batteries and causes the same overload and subsequent safety problem, this would not be considered a safety defect. It is just as likely that a volumetric type vehicle body, such as a tank grain trailer or dump truck, etc., could be incorrectly loaded as it is for flatbed trailer.

For instance, a grain trailer is sized to handle a safe legal payload of the lighter grains and have the sides high enough to safely retain the product while in transit. If an operator heaps a load of the heaviest grains he will more than likely exceed not only the GVWR, but also the local state weight laws.

If your interpretation is enforced it would require that we manufacture vehicles for single purpose use which would cause a tremendous duplication of equipment and would be a waste of our natural resources and energy.

You can see that a manufacturer has no control over the loading practices used on his equipment after the vehicle leaves his premises.

We would appreciate very much reconsideration of your position and would welcome the opportunity to make more detailed presentations of our position if you have further questions.

Charles J. Calvin President

PETROLEUM TANK TRAILER

A typical 9000 gallon aluminum petroleum tank trailer conforms to MC 306 and is designed to carry gasoline and/or fuel oil.

(Graphics omitted) Weight Summary Tank weight 10,000 lb GVW Trailer 64,900 lb Payload 54,900 Tractor weight 15,100 GCW 80,000lb

Loading Schedule Compartments Gasoline Fuel Oil Fuel Oil at 6.1 lb/gal at 7.17 lb/gal at 7.17 lb/gal 1 2000 gal 2000 gal 2000 gal 2 1875 gal 1875 gal 1875 gal 3 1350 gal EMPTY 1350 gal 4 1875 gal 1875 gal 1875 gal 5 2000 gal 2000 gal 2000 gal Total payload volume 9000 gal 7625 gal 9000 gal Total payload & trailer 64,900 lb 64,900 lb 74,530 lb GVWR 70,000 lb 70,000 lb 70,000 lb

Improperly loaded trailer results in a loaded weight which exceeds the GVWR by 4530 lb.

ID: nht79-4.16

DATE: 05/09/79

FROM: STEPHEN P. WOOD FOR FRANK BERNDT, NHTSA

TO: Management Consulting in Product Assurances

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your April 9, 1979, letter asking how the agency will apply the reporting requirements of Part 573, Defect and Noncompliance Reports, to equipment manufacturers.

As the agency indicated in the preamble to the final rule, replacement equipment manufacturers that are required to notify owners and to remedy defective or noncomplying equipment would do so to the best of their abilities. The reporting requirement does not require them to manufacture their equipment so that it is easily identifiable nor does it require them to maintain lists of persons to whom equipment has been sold. Some equipment manufacturers may wish to upgrade their recordkeeping and identification systems to facilitate their statutory obligations to recall and remedy, but the reporting regulation does not require this.

With respect to the "flasher" incident to which you refer in your letter, if a vehicle manufacturer authorizes the use of incorrect flashers in its vehicles, problems resulting from the use of those flashers would be the responsibility of the vehicle manufacturer not the equipment manufacturer. The problem that you describe is one of incorrect use of properly functioning equipment. It is not a problem of defective equipment.

Sincerely,