政策法规现行有效美国跨境陆运

§ 393.42 Brakes required on all wheels.

效力	法规类型	发布日期	生效日期	发文机构
现行有效	部门规章	2026-02-19	2026-03-23	Code of Federal Regulations (CFR) - Transportation (Title 49)

发布02-19

生效03-23

摘要总结AI 辅助解读

本法规（49 CFR § 393.42）规定所有商用机动车辆必须配备作用于所有车轮的制动器。针对特定拖挂操作（如driveaway-towaway、鞍座式组合）及轻型挂车（总重≤1,361 kg且轴重比符合40%限制）设有豁免条款。此外，1980年7月25日前制造的三轴及以上卡车前轮制动豁免，以及低速特种运输工具在满足特定制动距离要求下的豁免也予以明确。该规则直接影响美国境内陆运车辆的合规配置与检查标准。

(a) Every commercial motor vehicle shall be equipped with brakes acting on all wheels. This requirement also applies to certain motor vehicles being towed in a driveaway-towaway operation, as follows:

- (1) Any motor vehicle towed by means of a tow-bar when another motor vehicle is full-mounted on the towed vehicle; and

- (2) Any saddlemount configuration with a fullmount.

(b) Exception. (1) Trucks or truck tractors having three or more axles and manufactured before July 25, 1980, are not required to have brakes on the front wheels. However, these vehicles must meet the requirements of § 393.52.

- (2) Motor vehicles being towed in a driveaway-towaway operation (including the last truck of triple saddle-mount combinations (see § 393.71(a)(3)) are not required to have operative brakes provided the combination of vehicles meets the requirements of § 393.52.

- (3) Any semitrailer or pole trailer (laden or unladen) with a gross weight of 1,361 kg (3,000 pounds) or less which is subject to this part is not required to be equipped with brakes if the axle weight of the towed vehicle does not exceed 40 percent of the sum of the axle weights of the towing vehicle.

- (4) Any full trailer or four-wheel pole trailer (laden or unladen) with a gross weight of 1,361 kg (3,000 pounds) or less which is subject to this part is not required to be equipped with brakes if the sum of the axle weights of the towed vehicle does not exceed 40 percent of the sum of the axle weights of the towing vehicle.

- (5) Brakes are not required on the steering axle of a three-axle dolly which is steered by a co-driver.

- (6) Loaded housemoving dollies, specialized trailers and dollies used to transport industrial furnaces, reactors, and similar motor vehicles are not required to be equipped with brakes, provided the speed at which the combination of vehicles will be operated does not exceed 32 km/hour (20 mph) and brakes on the combination of vehicles are capable of stopping the combination within 12.2 meters (40 feet) from the speed at which the vehicle is being operated or 32 km/hour (20 mph), whichever is less.

ER15AU05.020

[52 FR 2803, Jan. 27, 1987, as amended at 53 FR 49398, Dec. 7, 1988; 54 FR 48617, Nov. 24, 1989; 59 FR 25574, May 17, 1994; 61 FR 1843, Jan. 24, 1996; 70 FR 48049, Aug. 15, 2005; 76 FR 56321, Sept. 13, 2011]