School of Public Policy, Georgia Institute of Technology, Atlanta, Georgia 30332-0345, USA.
J Air Waste Manag Assoc. 2011 Oct;61(10):996-1004. doi: 10.1080/10473289.2011.596738.
Based on requirements under the Clean Air Act Amendments of 1990, most state vehicle inspection and maintenance (I/M) programs have, since 2002, replaced the tailpipe emission testing with the on-board diagnostic (OBD) II testing for 1996 model and newer vehicles. This test relies on the OBD II system to give the pass or fail result, depending on certain conditions that might cause the vehicle to emit pollution 1.5 times higher than the regulated standard. The OBD II system is a computer and sensors installed in the vehicle to monitor the emission control units and signal if there is any malfunction. As a vehicle ages, its engine, pollution control units, and OBD II system deteriorate. Because the OBD II system's durability directly influences the test outcome, it is important to examine the fleetwide trend in the OBD II test results in comparison with an alternative measure of identifying high emitting vehicles. This study investigates whether the validity and reliability of the OBD II test is related to the age of the OBD II system installed in the fleet. Using Atlanta's I/M testing records and remote sensing device (RSD) data collected during 2002-2005, this research establishes the convergent validity and interobserver reliability criteria for the OBD II test based on on-road emissions measured by RSDs. The study results show that older vehicles exhibit significantly lower RSD-OBD II outcome agreement than newer vehicles. This suggests that the validity and reliability of the OBD II test may decline in the older vehicle fleets. Explanations and possible confounding factors for these findings are discussed.
基于 1990 年《清洁空气法案修正案》的要求，自 2002 年以来，大多数州的车辆检验和维护（I/M）计划已用车载诊断（OBD II）测试取代了 1996 年及以后车型的尾气排放测试。该测试依赖 OBD II 系统根据某些可能导致车辆排放超过规定标准 1.5 倍的条件给出通过或失败的结果。OBD II 系统是安装在车辆中的计算机和传感器，用于监测排放控制系统并发出信号，如果有任何故障。随着车辆的老化，其发动机、污染控制装置和 OBD II 系统会恶化。由于 OBD II 系统的耐用性直接影响测试结果，因此重要的是要检查 OBD II 测试结果在与识别高排放车辆的替代措施进行比较时的全车队趋势。本研究调查了 OBD II 测试的有效性和可靠性是否与车队中安装的 OBD II 系统的年龄有关。利用亚特兰大的 I/M 测试记录和 2002-2005 年期间收集的远程感应设备（RSD）数据，本研究基于 RSD 测量的道路排放，为 OBD II 测试建立了收敛有效性和观察者间可靠性标准。研究结果表明，较旧车辆的 RSD-OBD II 结果一致性明显低于较新车辆。这表明，在较旧车辆车队中，OBD II 测试的有效性和可靠性可能会下降。对这些发现的解释和可能的混杂因素进行了讨论。
