Interpretation ID: aiam1860
United States Senate
Washington
DC 20510;
Dear Senator Talmadge: This responds to your recent communication requesting consideration o a constituent's concern about the National Highway Traffic Safety Administration's standard requiring antiskid devices on new school buses for all states, although some states do not often have icy roads.; The regulation to which your constituent Mr. Smith refers is Federa Motor Vehicle Safety Standard No. 121, *Air brake systems*. This standard which became effective for trailers on January 1, 1975, and trucks and buses on March 1, 1975, specifies minimum performance requirements for service brake systems, emergency brake systems, and parking brake systems utilized on air-braked vehicles. The standard does not specifically require antilock devices, although S5.3.1 of the standard does specify minimum stopping distance and stability requirements on dry and wet roads. Most vehicle manufacturers have decided to utilize antilock devices to meet these requirements. The purpose of these requirements is to enhance vehicle stability during brake application on roads in all conditions, dry and wet, as well as icy. A copy of Standard No. 121 with amendments is enclosed.; Please write again if I can be of further assistance. Sincerely, James C. Schultz, Chief Counsel