The two related studies attempted to evaluate the effectiveness of roadside radio communication in behaviour of the driver as related to his execution of a diverging manoeuvre from a freeway traffic system. while information was being given to participants in each test condition, data on traffic characteristics of the driver were collected at various positions along the freeway and the deceleration lane prior to an exit ramp selected for the study. The results of data analysis indicated that audio messages were as effective as visual messages and when given together the performance of test drivers was generally better than the performance of test drivers with only visual or audio messages. Indications of this investigation were that a radio-signing system which will provide the necessary information where needed can be effective and at the same time avoid extensive over-signing. Additional research is required to determine the use of radio as a communication devise on a system basis.
Abstract