Interpretation ID: VICK
Mr. Greg Vickers
Truck Mixer Manufacturers Bureau
900 Spring Street
Silver Spring, MD 20910
Dear Mr. Vickers:
This responds to your letter to the National Highway Traffic Safety Administration (NHTSA), concerning Standard No. 121, Air Brake Systems. You were particularly interested in the antilock braking system requirements which become effective on March 1, 1998.
You explain that Truck Mixer Manufacturers Bureau (TMMB) member companies are final stage manufacturers. They usually purchase new chassis and "finish" them by mounting bodies, i.e., concrete mixers. You ask:
The question arises when you consider that TMMB members will potentially receive non-ABS-equipped chassis prior to March 1, 1998 and will subsequently complete manufacture of the vehicle after March 1. Please confirm that our members' trucks will be in compliance in such a case.
Our standards apply to any motor vehicle manufactured on or after the effective date of the standard. However, special provisions apply to vehicles manufactured in two or more stages. If your members purchase "incomplete vehicles," the vehicles may be completed to the standards in effect on the date of the manufacture of the incomplete vehicle, the date of final completion, or a date between those two dates.(1) In the example you provide, the date of manufacture of the incomplete vehicle would be prior to the effective date of the ABS requirements. Thus, the use of ABS would be optional for the final stage manufacturers.
You also ask about "another ABS related matter." You state:
Final stage manufacture of truck mixers frequently entails adding a liftable boost-a-load axle. Non-ABS brakes for the wheels on the added axle are tied into the air system of the chassis. The brake assemblies of the truck chassis are otherwise unaltered by the installer of the mixer body. TMMB would like verification that such addition of a liftable axle does not decertify the braking system of the chassis, provided the provisions for an additional certification label affixed to the completed vehicles are met.
Given that you are concerned whether the addition of a liftable axle would "decertify" the braking system of the chassis, we assume that you are asking about chassis-cabs.(2) As discussed below, the answer would depend on the type and nature of the certification statement made by the chassis-cab manufacturer. I note, however, that this agency cannot provide verification that the addition of a liftable axle would not affect a vehicle's compliance with Standard No. 121.
Under 49 CFR Part 567.5(a), the chassis-cab manufacturer is required to make a certification statement, with respect to each Federal motor vehicle safety standard, in one of three categories:
(1) The vehicle conforms to the standard,
(2) The vehicle will conform to the standard if it is completed in accordance with the instructions contained in the incomplete vehicle document (this statement is made with respect to standards conformity to which is substantially affected by the design of the chassis-cab and the manner in which the vehicle is completed), or
(3) Conformity with the standard is not substantially affected by the design of the chassis-cab.
The final stage manufacturer's certification responsibilities (49 CFR 567.5(c)) for a particular vehicle are dependent on the type and nature of the certification statements made by the chassis-cab manufacturer, and on the specific manufacturing operations performed by the final stage manufacturer. In the case of Standard No. 121, we assume the chassis-cab manufacturer would make a certification statement in the second category set forth above, i.e., a conditional statement. The final stage manufacturer could rely on this conditional statement only if it completed the vehicle in accordance with the chassis-cab manufacturer's instructions. See 49 CFR Part 567.5(c). If the final stage manufacturer did not complete the vehicle in accordance with those instructions, it would be responsible for ensuring compliance of the vehicle to Standard No. 121, and certifying such compliance. I also note that the addition of a liftable axle could affect compliance of a vehicle with other safety standards, including Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars.
I hope this information is helpful. If you have any further questions, please feel free to call Edward Glancy of my staff at (202) 366-2992.
Sincerely,
John Womack
Acting Chief Counsel
ref:568
d.10/7/97
1. See 49 CFR 567 and 568. Note that 568.6 also specifies that this provision shall, however, be superseded by any conflicting provisions of a standard that applies by its terms to vehicles manufactured in two or more stages. The ABS requirements include no such provision.
2. While incomplete vehicle manufacturers are required under 49 CFR Part 568 to provide information with all their vehicles concerning conformity to Federal motor vehicle safety standards, only chassis-cabs are required to be certified. See 49 CFR Part 567.