1.1 这些测试方法涵盖了两种ABS车辆行为的测量，这两种行为反映了当车辆配备一系列待评估的不同轮胎组时，轮胎湿牵引性能的差异。 1.1.1 距离某个选定速度的制动距离。 1.1.2 在制动操作期间缺乏对车辆的控制。当车辆在制动期间未遵循预期轨迹时，尽管熟练驾驶员有意识地努力保持轨迹控制，但仍会发生不可控。不可控性是通过一系列与预期轨迹偏差相关的参数以及车辆在停车机动过程中的运动来测量的。 1.1.3 尽管防抱死制动系统保持车轮旋转并允许高度的轨迹控制，但结构、胎面花纹和胎面胶不同的不同轮胎组除了停车距离外，还可能影响轨迹控制的程度。 因此，车辆不可控性是轮胎湿牵引性能的重要评价参数。 1.2 这些试验方法规定在两个专门准备的试验课程上进行湿式制动牵引试验: (1) 一条直线（直线）“分裂-µ”（µ=摩擦系数）试验路线，沿试验路线部署两条试验车道（试验车辆行驶时）；两条车道的摩擦水平相差很大，因此左一对车轮在一个表面上行驶，而右一对车轮在另一个表面上行驶；和 (2) 曲线轨迹恒定路径半径课程，两个车轮车道的路面均匀。 1.3 与所有可能导致车辆失控的牵引试验一样，应采取足够的预防措施，以保护驾驶员、车辆和试验现场设施，使其在试验期间不会因车辆牵引脱离而受损。 标准预防措施包括防滚翻杆、所有内部仪表的安全安装、驾驶员头盔和安全带线束等。 1.4 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 制动牵引力是车辆控制的一个重要因素，尤其是在潮湿路面上。这些测试方法允许在配备ABS的车辆上评估轮胎的相对或比较性能。看见 附件A1 用于解释结果和有意义地评估轮胎设计特征对湿牵引性能的影响的背景信息。 5.2 虽然停车距离对于车辆控制很重要，但在选定轨迹上驾驶车辆的能力同样重要，或者在某些情况下更重要。轮胎的湿牵引能力会影响这两个测量参数，因为轮胎是ABS和路面之间的链路，并提供牵引力或轮胎附着力水平，从而允许ABS按预期工作。 5.3 通过这些测试方法获得的参数绝对值在很大程度上取决于车辆的特性、ABS的设计特征、选定的测试路面以及测试过程中的环境和测试条件（例如，环境温度、水深、测试速度）。这些因素中任何一个的变化都可能改变绝对参数值，也可能改变如此测试的轮胎的相对额定值。 5.4 这些试验方法适用于研究和开发目的，其中在短暂的试验期间比较轮胎组。它们可能不适用于监管或规范验收目的，因为获得的值可能不一定与在其他条件下获得的值（例如，同一测试过程中的不同位置或不同季节时段）一致或相关，无论是按秩顺序还是绝对值。

1.1 These test methods cover the measurement of two types of ABS vehicle behavior that reflect differences in tire wet traction performance when the vehicle is fitted with a series of different tire sets to be evaluated. 1.1.1 The stopping distance from some selected speed at which the brakes are applied. 1.1.2 The lack of control of the vehicle during the braking maneuver. Uncontrollability occurs when the vehicle does not follow the intended trajectory during the period of brake application despite a conscious effort on the part of a skilled driver to maintain trajectory control. Uncontrollability is measured by a series of parameters related to this deviation from the intended trajectory and the motions that the vehicle makes during the stopping maneuver. 1.1.3 Although anti-lock braking systems maintain wheel rotation and allow for a high degree of trajectory control, different sets of tires with variations in construction, tread pattern, and tread compound may influence the degree of trajectory control in addition to stopping distance. Thus vehicle uncontrollability is an important evaluation parameter for tire wet traction performance. 1.2 These test methods specify that the wet braking traction tests be conducted on two specially prepared test courses: (1) a straight-line (rectilinear) “split-µ” (µ = friction coefficient) test course, with two test lanes deployed along the test course (as traveled by the test vehicle); the two lanes have substantially different friction levels such that the left pair of wheels travels on one surface while the right pair of wheels travels on the other surface; and (2) a curved trajectory constant path radius course with uniform pavement for both wheel lanes. 1.3 As with all traction testing where vehicle uncontrollability is a likely outcome, sufficient precautions shall be taken to protect the driver, the vehicle, and the test site facilities from damage due to vehicle traction breakaway during testing. Standard precautions are roll-bars, secure mounting of all internal instrumentation, driver helmet, and secure seat belt harness, etc. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parenthesis are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Braking traction is an important factor in vehicle control especially on wet pavements. These test methods permit an evaluation of tires for their relative or comparative performance on an ABS-equipped vehicle. See Annex A1 for background information for interpretation of results and meaningful evaluation of tire design features for their influence on wet traction performance. 5.2 Although stopping distance is important for vehicle control, the ability to steer the vehicle on a selected trajectory is equally or, in some instances, more important. The wet traction capability of tires influences both of these measured parameters since the tires are the link between the ABS and the pavement and provide the traction or tire adhesion level that permits the ABS to function as intended. 5.3 The absolute values of the parameters obtained with these test methods are highly dependent upon the characteristics of the vehicle, the design features of the ABS, the selected test pavement(s), and the environmental and test conditions (for example, ambient temperature, water depths, test speeds) at the test course. A change in any of these factors may change the absolute parameter values and may also change the relative rating of tires so tested. 5.4 These test methods are suitable for research and development purposes where tire sets are compared during a brief testing time period. They may not be suitable for regulatory or specification acceptance purposes because the values obtained may not necessarily agree or correlate, either in rank order or absolute value, with those obtained under other conditions (for example, different locations or different seasonal time periods on the same test course).