Interpretation ID: aiam2143
Manager
Product Safety and Quality
Volvo of America Corporation
Rockleigh
NJ 07647;
Dear Mr. Taylor: This responds to Volvo of America's October 9, 1975, question whether truck equipped with an air-assisted hydraulic brake system with hydraulic push through capability and, in the towing vehicle configuration, a source of compressed air for air braked trailer operation is subject to Standard No. 121, *Air Brake Systems*.; From your description of the system and the materials that accompanie your letter, the truck does not qualify as an air-braked vehicle to which the standard applies. The fact that it is capable of operation in combination with an air-braked vehicle and supplies the compressed air for braking that vehicle does not affect the truck's classification as an hydraulic-braked vehicle.; At the time Standard No. 121 was developed, it covered virtually all o the trucks and truck- tractors in the heaviest categories. In planning and making your decisions to introduce hydraulic-braked vehicles in these weight categories, you should be aware that this agency is planning to cover all such vehicles with the basic performance requirements presently contained in Standard No. 121.; Sincerely, Frank Berndt, Acting Chief Counsel