Modeling Urban Travel Time Variability by Analyzing Delay Distribution for Signalized Urban Trips

摘要

It is widely accepted that travel times in urban road networks can vary largely, both within a shorttime period and from period to period in a single day. One important cause for this variability in urbantravel times is the delay that drivers experience at (particularly signalized) intersections. This delaycan be due to the time that the driver needs to wait for the red light or the time for the queue ofwaiting vehicles at the intersection to dissolve, or both. As a result, the ability to capture thecharacteristics of the delay at signalized intersections is a critical, yet challenging, step in estimatingand predicting urban link travel times. The uncertainties in these experienced delays are caused byboth the traffic conditions and traffic control at the intersections. In this paper, a delay distributionmodel is developed for an urban trip over a route with two consecutive fixed-time controlledintersections. The proposed model captures the stochasticity in the arrival and departure process at thefirst intersection. The presented example illustrates how these stochastic factors influence the realizeddelay distribution for the two consecutive signalized intersections. Delay distributions are analyzedfor different levels of mismatch of the two controlled intersections (from well coordinated to badlycoordinated), and under different degrees of saturation. Finally, the predicted delay distributions arevalidated using the VISSIM simulation model, and show that the proposed (analytical) model can wellrepresent the VISSIM simulation data.