Driver behaviour at traffic signals.

This paper describes the development of a dynamic framework for the modelling of driver behaviour at traffic signals which allows investigation of the effects of altering certain parameters on the situations in which drivers may find themselves. The objective of the study as a whole was to develop a behavioural model of drivers' responses to the changing of traffic signals at the end of the green, the model being so formulated that it could be used to estimate the effects on drivers responses of a range of possible modifications to the way in which the signals change from green for one set of traffic streams to green for other conflicting streams. Although it is not the purpose his paper to discuss the results of the field observations in detail, the representation does indicate some aspects of the situation which are of considerable interest. About half of the red runners at this site should have been able to clear successfully with zero acceleration. The implication of this is that the vehicles slowed down for some reason, this could be due to a change of mind about whether to attempt to go, or due to balking by other vehicles. This needs to be investigated further. Relatively few red runners were in the no option situation, even with an assumed response time of 1.5s. A number of individuals who stopped successfully could have cleared (with zero acceleration), and some stopped successfully even though they required relatively high deceleration rates (assuming a1s response time). Most drivers that cleared successfully would not have been capable of stopping successfully. For a full report of this work see TRRL contractor report CR 264).