Real-Time Estimation of Travel Times on Signalized Arterials

Continuous traffic growth through developed areas and difficulties in building new infrastructure have caused a need for careful monitoring of operating conditions on existing transportation facilities and development of improved strategies to manage the increase in traffic demand.  The analysis of existing conditions and evaluation of alternative improvements requires estimates of performance measures of both system operators and users.  Travel time is an important measure to assess the existing operating conditions along signalized arterials, evaluate control and management strategies and provide information to travelers.  This paper proposed an analytical model to estimate travel time on arterial streets based on data commonly provided by system loop detectors (flow and occupancy) and the signal settings (cycle length, green times and offsets) at each traffic signal.  The model is based on kinematic wave theory to model the spatial and temporal queuing at the traffic signals and explicitly considers the signal coordination in estimating traffic arrivals at the intersection.  The model is straightforward to implement and unlike other approaches does not depend on site specific parameters or short term traffic flow predictions that make very difficult their transferability to other locations.