Stated acceptance and behavioral responses of drivers towards innovative connected vehicle applications.

This research is aimed at investigating drivers' attitudes towards connected vehicle technology in general and two connected vehicle applications in particular-Lane Speed Monitoring and High Speed Differential Warning-which have been demonstrated via simulation to be effective in enhancing traffic mobility and safety, respectively. An online survey was sent to customers of an automobile manufacturer in the United States. Out of the 1453 survey responses that were received, 650 complete and valid responses were used to analyze the respondents' stated acceptance of and expected behavioral responses to the two connected vehicle applications under a variety of scenarios. Statistical analyses were conducted to examine the influence of demographic and socioeconomic factors. The results reveal that the respondents express high willingness to use connected vehicle technology and the two applications under various circumstances, and the willingness is strongly associated with age, gender, education level, and income. Higher levels of acceptance are observed in older, male, higher-educated, or higher-income respondents, while the patterns of conditional acceptance and expected behavioral responses vary with specific scenarios. These results provide useful information for application developers, traffic operators, and policy makers to steer connected vehicle technology development and deployment in the direction that will benefit both the users and the society.

[Study of on-board emission measurement for heavy-duty diesel vehicle and its impact with load].

Real world vehicle emission tests were conducted on two heavy-duty diesel trucks on un-loaded and loaded condition by using a portable emission measurement system. By analysis, the results indicate high fuel consumption and emission rates are concentrated on the high speed and acceleration areas of the speed-acceleration emission maps and the areas are much wider on loaded condition. The impact of load on fuel use and emissions will be highest while the vehicle is cruising or accelerating on (30 +/- 2.5) km x h(-1), which are 1.6 - 3.2 times of those on un-loaded condition. Synthetically, the comprehensive fuel consumption and CO, HC, NO(x) emission factors of truck I and truck II on loaded condition are respectively 1.6, 3.5, 1.1, 1.5 times and 1.2, 1.0, 0.9, 1.5 times of those without load. Load has greatest impact on fuel consumption and NO(x) emission and less effect on HC emission. As for the CO emission, it depends on the maintenance of the truck. It can be figured out from the results on two trucks that the impact of same load will be lower on a vehicle with lager type and more powerful engine, which means if one vehicle is loaded on its acceptable range of GVWR, fuel use and emissions caused by heavy loads could be decreased correspondingly.