This paper describes a simulator study in Florida, USA, investigating the number of phases used in changeable message signs (CMS) and the length of their display. Simulator screens presented interactive road and traffic conditions while the supplemental monitor displayed the CMS. Young and old drivers were surveyed. Results showed consistent and significant age effects, and significantly poorer response for all drivers viewing a two-phase CMS. The findings have implications for CMS design and operation.
Samenvatting