基于活动方法的瓶颈模型与拥挤收费问题研究

Vickrey提出的基于出行的瓶颈模型以出行作为分析单位,没有考虑出行与活动之间的相互关联.本文对Vickrey的瓶颈模型进行了拓展,提出了基于活动的瓶颈模型来研究通勤者早晨上班出发时间决策问题,模型考虑了通勤者对出行负效用与活动效用之间的权衡.在基于活动的瓶颈模型的基础上,分别研究了常数和线性边际活动效用下瓶颈动态拥挤收费和阶梯收费问题,并与传统的瓶颈模型的解进行比较.结果表明,当活动的边际效用为线性函数时,瓶颈处最优动态收费曲线不再呈分段线性关系,而是分段二次曲线;与基于活动的瓶颈模型相比,传统的基于出行的瓶颈模型将高估瓶颈处的排队延误、阶梯收费水平,以及早高峰的开始和结束时间;基于出行的瓶颈模型和常数边际活动效用下的瓶颈模型导致的最优阶梯收费是最优动态收费最大值的一半,并且刚好消除瓶颈处排队延误的一半;与线性边际活动效用下的瓶颈模型相比较,两者低估了阶梯收费能消除的瓶颈排队,从而低估了阶梯收费的效率.

Activity-based bottleneck model and congestion toll pricing issues

The Vickrey's bottleneck model adopted a trip-based approach,which cannot consider the linkage between the commuter's activity schedule and trip.This paper extends the Vickrey's bottleneck model to address the departure time choice in the morning peak by introducing an activity-based bottleneck model.This model explicitly considers the commuter's trade-off between the utility received by activities at home and at work and the disutility of travel between activity locations.The optimal time-varying toll and step toll are then investigated by using the activity-based bottleneck models with constant and linear marginal activity utility functions.The optimal toll solutions are also compared with the traditional Vickrey's bottleneck model.The results show that the curve of the optimal solution for the time-varying toll is not piecewise linear but piecewise quadratic when the marginal activity utility is linear.The traditional Vickrey's bottleneck model overestimates the queuing delay at the bottleneck,the step toll level,and the start time and end time of the morning peak period.The optimal step tolls under the trip-based bottleneck model and the bottleneck model with constant marginal activity utility are half of the maximum value of the optimal time-varying tolls and exactly eliminate half of the total queuing delay at the bottleneck.The trip-based bottleneck model and the bottleneck model with constant marginal activity utility underestimate the role of step tolls in removing the bottleneck queues compared to the bottleneck model with the linear marginal activity utility.