Variable-message sign

Abstract: Variable message signs (VMS) have been installed in London to notify motorists of planned events and current network problems. To guide investment and operational decisions an understanding is required of the impacts of VMS information. This paper presents the results of a study of driver response to VMS information. The study employed questionnaires to investigate the effect of different messages on route choice. A statistical analysis of stated intention questionnaire data enabled logistic regression models to be developed relating the probability of route diversion to driver, journey and message characteristics. The resultant models indicate that the location of the incident and the message content are important factors influencing the probability of diversion. A survey of drivers' actual responses to a message activation showed that only one third of drivers saw the information presented to them and few of these drivers diverted, although many found the information useful. Only one-fifth of the number of drivers diverted compared to that expected from the results of the stated intention questionnaire. It is thought that the low response rate achieved for the stated intention survey will have exaggerated drivers' responsiveness to VMS messages. Interestingly, survey data for another UK city with a newly installed VMS system showed that the number of drivers diverting due to VMS information was very similar to that expected from the results of the stated intention questionnaire. It is suggested that the use of London's VMS signs to display warnings of disruptions expected on future dates may be reducing their effectiveness as a channel for more urgent warnings.

Abstract: A method and system in automobile traffic control for warning drivers that they are exceeding the speed limit using an alpha-numeric variable message sign (50) proximate the roadway. The sign displays the license plate number, owner's name and the vehicle's speed. The system includes an opto-electric license plate reader (10) and a computer system (31) having a database of license numbers and associated information, including owner's names and make and model of licensed vehicles.

Abstract: In this paper we analyse the impact of both radio traffic information and variable message sign information on route choice behaviour. The empirical analysis is based on an extensive survey held among road users in the Amsterdam corridor in July 1994. The data is stemming from the EC DRIVE II project BATT. To analyse the factors that influence route choice behaviour, several types of discrete choice models (ordered probit, multiple logit and bivariate ordered probit) have been estimated. Bivariate models are needed to model the (endogenous) dependency of the use of radio traffic information and variable message sign information. The results confirm earlier findings that women are less likely to be influenced by traffic information. New is the finding that commuters are less likely to be influenced, and that the level of satisfaction with alternative routes is strongly related to the type and distance of the alternative road. The analysis also reveals that the impacts of radio traffic information and variable message sign information on route choice behaviour are very similar, and that route choice adaptations based on radio traffic information are positively related to route choice adaptations based on variable message sign information. An interesting issue is the willingness-to-pay for having in-vehicle dynamic traffic information. As expected, the willingness-to-pay is relatively large for male drivers on business trips. Another important new finding is that the results suggest that there is a positive correlation between the use of radio traffic information and variable message sign information.

Abstract: DynaMIT is a simulation-based real-time system designed to estimate the current state of a transportation network, predict future traffic conditions, and provide consistent and unbiased information to travelers. To perform these tasks, efficient simulators have been designed to explicitly capture the interactions between transportation demand and supply. The demand reflects both the OD flow patterns and the combination of all the individual decisions of travelers while the supply reflects the transportation network in terms of infrastructure, traffic flow and traffic control. This paper describes the design and specification of these simulators, and discusses their interactions.