Arterial Travel Time Estimation for Advanced Traveler Information Systems

While vehicular flows on freeways are often treated as uninterrupted flows, flows on arterials are conceivably much more complicated since vehicles traveling on arterials are not only subject to queuing delay but also to signal delay. Prediction of travel time is potentially more challenging for arterials than for freeways. This paper proposes a simple approach for arterial travel time prediction. The proposed approach decomposes total delay on an arterial into link delay and intersection delay. Intersection delay in the context of arterial travel time prediction is different from the average delay at an intersection. The proposed approach reduces the continuous delay experienced by drivers at each intersection into two distinctive states, a state of zero-delay and a state of nominal delay, coupled with a one-step transition matrix that relates the delay to a through vehicle at an intersection to its delay status at the adjacent upstream intersection. The parameters of the transition matrix are based on three key factors, the flow condition at the intersection, the proportion of net inflows into the arterial from the cross streets, and the signal coordination level. Numerical results show that the model can yield predictions with a reasonable degree of accuracy under various traffic conditions and signal coordination levels.