Reducing emissions from in-use vehicles: an evaluation of the Phoenix inspection and maintenance program using test results and independent emissions measurements

Various federal regulations require states to evaluate the effectiveness of their vehicle inspection and maintenance (I/M) programs in reducing in-use emissions. One method to evaluate program effectiveness is to compare initial and final program test results of individual vehicles. Unscheduled emissions measurements, from remote sensing measurement or roadside pullover testing, can also be used to provide an independent assessment of program effectiveness. We compared emissions reductions from the Arizona IM240 program measured by program data and a large set of remote sensing measurements. Remote sensing measurements indicate smaller emission reductions from the program than those calculated directly from program test results. We discuss some possible causes of the differences obtained from the two sets of measurements.     

不同类型机动车尾气中芳香烃化合物含量分析

首次对北京市9种车辆、5种燃料在不同工况下排放芳香烃化合物的特征．进行了定量研究。结果表明,车型、燃料、净化器及工况等因素对排放量产生影响,电喷车比化油器车芳香烃化合物排放量低;汽油车排放量最高,柴油车其次,LPG及CNG车排放量最低;使用净化器可以降低芳香烃排放量;不同工况对排放量的影响随车型,燃料类型的不同而不同。     

美国资产证券化中的政府作用对我国的借鉴

美国政府在资产证券化创设过程中发挥了巨大的作用。为推动我国资产证券化的开展，我国政府可借鉴美国做法，采取修订法律、营造金融环境、设置政府机构等措施。     

福州市机动车污染及其控制对策

通过对福州市城区道路的车流量及车辆构成状况的调查，估算城市中心区域机动车排气CO、THC和NO2的污染物排放量，分析不同车型的机动车排气污染和贡献率，提出对机动车排气污染的控制对策措施。     

车轮通用打字模设计

根据本单位生产设备特点及车轮的工艺要求，进行工艺分析，设计实用、可靠、灵活、操作简便的通用打字模。     

我国在用汽车排气污染物检测方法及应用进展

我国两项在用汽车排放标准于2005年发布以来,新规定检测方法的优点、技术特征为广大机动车环保工作者所关注。为对在用汽车检测技术有一较全面的认识,本文对各种检测方法的要点进行阐述,同时介绍一些国内城市检测工作的研究和进展。     

Modeling vehicle emissions in different types of Chinese cities: importance of vehicle fleet and local features

We propose a method to simulate vehicle emissions in Chinese cities of different sizes and development stages. Twenty two cities are examined in this study. The target year is 2007. Among the cities, the vehicle emission factors were remarkably different (the highest is 50-90% higher than the lowest) owing to their distinct local features and vehicle technology levels, and the major contributors to total vehicle emissions were also different. A substantial increase in vehicle emissions is foreseeable unless stronger measures are implemented because the benefit of current policies can be quickly offset by the vehicle growth. Major efforts should be focused on all cities, especially developing cities where the requirements are lenient. This work aims a better understanding of vehicle emissions in all types of Chinese cities. The proposed method could benefit national emission inventory studies in improving accuracy and help in designing national and local policies for vehicle emission control.     

Do NHTSA vehicle safety ratings affect side impact crash outcomes?

Introduction: Side impact crash injuries tend to be severe, mainly due to the effects of the mechanism of such crashes. This study addresses the relationship between side impact crash injury severities and side impact safety ratings of the passenger cars involved in such crashes. It is motivated by the lack of research on side impact safety ratings in relation to the real-world crash outcomes. Method: Analysis of Crashworthiness Data System’s (CDS) data show the head and thorax are the most common regions of impact of severe injuries, while the neck is the least. Irrespective of body regions, higher-rated vehicles were found to provide better occupant protection to both younger and older driver age groups. Assessment based on injury severity score (ISS) indicates that higher-rated vehicles have an overall lower average ISS compared to lower-rated vehicles. Results: Ultimately, this study shows that vehicles rated with National Highway Traffic Safety Administration’s (NHTSA) new criteria had lower average ISS compared to vehicles rated under the old criteria. The 2011 NHTSA side impact rating criteria being relatively new, it has very few crashes to draw meaningful statistically significant conclusions. However, this paper establishes the fact that vehicles with higher star ratings (under experimental conditions) indeed offer increased occupant protection in the field conditions. Practical applications: Previous studies have found that safety was given priority while buying new vehicles. However, people associated vehicle safety with technologies and specific safety features rather than the vehicle’s crash test results or ratings (Koppel, Charlton, Fildes, & Fitzharris, 2008). The results from this study provide a point of reference for safety advocates to educate the drivers about the importance of considering vehicle safety ratings during a vehicle purchase.     

The effects of daylight saving time on vehicle crashes in Minnesota

Introduction: Daylight saving time (DST), implemented as an energy saving policy, impacts many other aspects of life; one is road safety. Based on vehicle crash data in Minnesota from 2001 to 2007, this paper evaluates long- and short-term effects of DST on daily vehicle crashes. Method: To provide evidence to explain the causes of more/fewer crashes in DST, we examine the impact of DST on crashes in four periods of a day: 3 a.m.-9 a.m., 9 a.m.-3 p.m., 3 p.m.-9 p.m., 9 p.m.-midnight. The effects of risk and exposure to traffic are also separated. Our statistical models not only include weather conditions and dummy variables for days in DST as independent variables, but also consider traffic volumes on major roads in different periods of a day. Our major finding is that the short-term effect of DST on crashes on the morning of the first DST is not statistically significant. Moreover, it is interesting to notice that while DST per se is associated with fewer crashes during dusk, this is in part offset because it is also associated with more traffic on roads (and hence more crashes). Our path analysis shows that overall DST reduces crashes. Impact on industry: Daylight saving time can lead to fewer crashes on roads by providing better visibility for drivers.