Diversion during unexpected congestion on toll roads: the role of traffic information displayed on dynamic message signs

Dynamic message signs (DMS) are electronic signs displayed on roadways, providing travel times, traffic congestion, AMBER alerts, and special events. Orlando-Orange County Expressway Authority (OOCEA) in Florida added 29 fixed DMS to their toll road network between 2006 and 2008. The research issues investigated in this study are: 1) whether use of dynamic information on toll roads is associated with route diversions, and 2) are users satisfied with the available dynamic information? The instrument used to analyse traveller´s perception of DMS and traffic information was a survey conducted in Central Florida region in May 2008 using Computer Aided Telephone Interview. Respondents answered questions on knowledge of DMS on OOCEA toll roads, satisfaction with travel information provided on the network and with different aspects of messages, route diversion (revealed and stated preferences), and demographics. A multinomial logit model was estimated to quantify the odds of choosing different diversion alternative over the alternative of ´stay´ that elucidated the differences in diversion behaviour. Results showed that factors associated with greater route diversion are longer travel times, longer delays, information sources, network familiarity, and trip characteristics. Respondents were generally satisfied with DMS. Hazard warnings and accuracy of dynamic information were deemed important for satisfaction.