Quantifying Vehicular Emission Factors With the Impact of Lane-changing Behavior on Different Types of Weaving Segment of Freeways

摘要

Motor vehicles, which can be implied as the mobile sources, are one of the primary causes of air pollution in USA. According to the US Environmental Protection Agency (EPA), there is a significant increase in the total emissions of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NO_x), greenhouse gases (GHG) especially carbon dioxide (CO_2), particulate matter (PM) and air toxics from motor vehicles from 2013 to 2014, which incorporates 27% of total U.S. GHG emissions. The basic factors of vehicle emissions are related to vehicle properties, pavement condition, roadway geometry, and especially driving behavior. With the unpredictable driving behavior, a series of acceleration and deceleration have been seen in the driving pattern while merging with and diverging from the through traffic within the weaving segments on a freeway. In addition, the traffic loads during different time of a day also significantly influence driver's lane changing behaviors and speed adaptations. The objective of this paper is to quantify and investigate the correlation between the vehicular emission and lane-changing maneuver in the weaving sections of freeways. A portable emission measurement system (PEMS) has been used to measure emissions during the actual use of an internal-combustion engine of a light-duty vehicle while driving in weaving segments of SH-288, Texas, USA. A video recorder and GPS tracker were used to document the vehicle trajectory and surrounding traffic demands. The statistical analysis showed that, with the peak-hour traffic conditions, driving pattern in weaving sections in accordance to the lane-changing behavior resulted an increase in CO_2 emission and fuel consumption compared to driving on the basic freeway segments. With further studies, the findings of this research can contribute in developing design consideration of the weaving sections in the reduction of vehicular emissions, which is a major concern for both environment and health.