Evaluating Toll Facility Signage Sequence through FLASH-Based Simulation

The National Surface Transportation Policy and Revenue Study Commission has recognized the great potential of congestion pricing in reducing congestion and improving system efficiency due to its ability to promote the efficient use of existing infrastructure. In a congestion pricing system, the design and implementation of the tolling signage is extremely essential in explaining tolling strategies to potential users. However, there is a lack of suitable testing and evaluation tool with lower cost and higher flexibility that can simulate the dynamics of sign movements in a driver's view and test drivers' understanding to sign sequences. This paper aims at developing an alternative tool, the FLASH simulation based test with an evaluation algorithm, to assess different signage sequences for toll facilities. The developed simulation test procedure composes of six operational steps, and the evaluation algorithm is answer-to-questionnaire based. To illustrate the proposed procedure and algorithm, a case study of newly designed tolling signs by Texas Department of Transportation was conducted. By following the procedure, the best scenario(s), with drivers' best understandings, were selected in each candidate sign sequence group. The developed method, although is originally intended for congestion pricing message signage and sign sequence in this paper, can be easily applied to other types of sign tests with more complicated vehicle operation schemes.