§ 393.49 Control valves for brakes.
发布02-19
生效03-23
摘要总结AI 辅助解读
本条款规定美国联邦法规第49篇关于制动控制阀的技术标准。核心要求是：1953年6月30日后制造且配备动力制动的机动车，其制动系统必须设计为通过单个应用阀即可激活所有行车制动器。该规定允许车辆额外配备用于拖车或巴士的独立阀门，但不得违反单阀主控原则。例外情形包括未采用单阀设计的甩挂运输（Driveaway-Towaway）及符合特定条件的惯性制动拖车。此规范直接影响跨境陆运车辆的合规准入与设备配置。
- (a) General rule. Except as provided in paragraphs (b) and (c) of this section, every motor vehicle manufactured after June 30, 1953, which is equipped with power brakes, must have the braking system so arranged that one application valve must when activated cause all of the service brakes on the motor vehicle or combination motor vehicle to operate. This requirement must not be construed to prohibit motor vehicles from being equipped with an additional valve to be used to operate the brakes on a trailer or trailers or as required for buses in § 393.44.
- (b) Driveaway-Towaway Exception. This section is not applicable to driveaway-towaway operations unless the brakes on such operations are designed to be operated by a single valve.
- (c) Surge brake exception. This requirement is not applicable to trailers equipped with surge brakes that satisfy the conditions specified in § 393.48(d).
[72 FR 9871, Mar. 6, 2007, as amended at 78 FR 58484, Sept. 24, 2013]