The Interaction Between Route Guidance and Signal Control: Model Results.

A multiple user class assignment model is developed to simulate the interaction between a route guidance system and an urban traffic control system. For two real- life networks of Leeds and Southampton four basic scenarios are investigated: current situation; - expected situation with route guidance but without interaction with the traffic control system; - expected situation with route guidance and with interaction with the traffic control system; - optimum future situation with 100% take-up and compliance with system optimal guidance and delay minimising signal control. The computed extra travel time savings of an integration of route guidance and signal control are of a similar magnitude as those of a route guidance system alone. With static demand delay minimisation performs best, but when demand is dynamically increasing Smith's Po policy gives rise to lowest network travel times. The degrading effect of imperfect advice or non-compliance is small at realistic levels of take-up of up to 25%. Along the same line, the benefits of system optimal guidance are also modest (in the order of less than 1%) when take-up of guidance is less than 25%.