On May 17th, 2017, in Room A928 of the New Main Building, Dr. Zhichun Li, a Professor of Huazhong University ofScience and Technology, was invited to give a lecture entitled "Steptolling in an activity-based bottleneck model". The lecture was hosted by Associate professor Tianliang Liu. More than 20 audiences attended, including professors, graduate and undergraduate students from School of Economics and Management and School of Transportation Science and Engineering, Beihang university.
In this lecture, Prof. Li introduced the bottleneck model of Vickrey (1969), which has been widely recognized as a useful tool for modeling the formation and dissipation of queuing at a bottleneck during the morning peak. There are three kinds of behavioral assumptions used for modeling step tolling in the bottleneck, respectively, the ADL model, the Laih model and the braking model of Lindsey. Prof. Li found that the the optimal step toll scheme with linear marginal activity utilities follows a symmetric (or shoulder) toll structure. And for a given number oftoll steps, the efficacy of a step toll in terms of queuing removal rate is higher in the activity-based bottleneck model with linear marginal activity utilities than in the conventional bottleneck model with constant marginalactivity utilities. The heterogeneity of user preferences is incorporated inthe activity-based bottleneck model and the step tolling problem. It is found that heterogeneous groups sequentially depart in order of decreasing marginalwork utility or increasing marginal home activity utility, and ignoring the preference heterogeneity of commuters can cause an underestimation of the efficacy of a step toll. After the lecture, Prof. Li conducted further discussions with the audience. The lecture has been widely welcomed by the audience.
