弹性需求下路段行程时间波动的收敛性

分析了弹性需求下路段行程时间的波动随道路长度延伸的收敛性.采用 MITSIM仿真路段上车辆的行驶过程，根据仿真数据计算车辆通过该路段的预期行程时 间，路段入口处的交通需求由需求函数及预期行程时间确定.通过记录所有车辆驶入、驶 出该路段的时刻获取车辆的实际行程时间.用行程时间标准差系数来衡量行程时间波动 性.数值算例对不同潜在交通需求的情况进行分析.结果表明，对任意确定的潜在需求，在 弹性需求的作用下，路段行程时间的波动性都将随着路段长度的延长而趋向收敛，随着 潜在交通需求的增加收敛速度减小，弹性系数的增加则促进行程时间波动的收敛.

Convergence of Travel Time Fluctuations in Elastic Demand

The convergence of travel time fluctuations in elastic demand is analyzed. MITSIM is adopted to simulate the process of the vehicles running on the road. The expected travel time is estimated by the simulation data before the vehicle go through the road segment. Traffic demand is determined by demand function and expected travel time. While one vehicle enters into the road, the time is recorded. When one vehicle exits the road, the time is recorded, too. The actual travel time of the vehicle is computed by the recorded data. Coefficient of standard deviation is used to measure the amplitude of travel time fluctuations. The results show that the travel time fluctuations converge as the extension of the road for any latent demand, that the convergence rate is reduced with the latent traffic demand increasing and that the convergence rate is improved with the elastic coefficient increasing.