title: Delay correction model for estimating bus emissions at signalized intersections based on vehicle specific power distributions.
abstract: The intersection is one of the biggest emission points for buses and also the high exposure site for people. Several traffic performance indexes have been developed and widely used for intersection evaluations. However, few studies have focused on the relationship between these indexes and emissions at intersections. This paper intends to propose a model that relates emissions to the two commonly used measures of effectiveness (i.e. delay time and number of stops) by using bus activity data and emission data at intersections. First, with a large number of field instantaneous emission data and corresponding activity data collected by the Portable Emission Measurement System (PEMS), emission rates are derived for different vehicle specific power (VSP) bins. Then, 2002 sets of trajectory data, an equivalent of about 140,000 sets of second-by-second activity data, are obtained from Global Position Systems (GPSs)-equipped diesel buses in Beijing. The delay and the emission factors of each trajectory are estimated. Then, by using baseline emission factors for two types of intersections, e.g. the Arterial @ Arterial Intersection and the Arterial @ Collector, delay correction factors are calculated for the two types of intersections at different congestion levels. Finally, delay correction models are established for adjusting emission factors for each type of intersections and different numbers of stops. A comparative analysis between estimated and field emission factors demonstrates that the delay correction model is reliable.
authors: MOE Key Laboratory for Urban Transportation Complex Systems, Theory and Technology, Beijing Jiaotong University, 3 Shangyuan Cun, Haidian District, Beijing 100044, PR China. Electronic address: GhSong@bjtu.edu.cn.
authors: Guohua
authors: G
authors: Song
authors: Chongqing Transport Planning Institute, 18 Yanghe 2nd Cun, Jiangbei District, Chongqing 400020, P. R. China.
authors: Xixi
authors: X
authors: Zhou
authors: MOE Key Laboratory for Urban Transportation Complex Systems, Theory and Technology, Beijing Jiaotong University, 3 Shangyuan Cun, Haidian District, Beijing 100044, PR China; College of Science and Technology, Texas Southern University, 3100 Cleburne Avenue, Houston, TX 77004, United States.
authors: Lei
authors: L
authors: Yu
keywords: Control delay; Delay correction factor; Emission factors; Transit bus