Use of Symbols on Truck-Mounted Changeable Message Signs for Work Zone Operations
Ullman, Brooke R.; Trout, Nada; Sun, Dazhi
The use of truck-mounted changeable message signs (TMCMSs) for scheduled and unscheduled short duration work operations is desirable for providing drivers with information to better prepare them for unexpected conditions. Traditionally, temporary traffic control for short duration operations has been limited to arrow boards and sometimes static warning messages mounted to the work vehicle. However, due to advances in technology, TMCMSs can fill an information gap for these operations and provide drivers with better information regarding both the operation and the expected actions based on the operation.
Through a human factors laboratory study, researchers evaluated message designs that incorporated both text and graphic alternatives for warning drivers about an accident, work zone area, and lane closures. In this study, researchers determined many key points regarding motorist interpretation of TMCMS symbol and text messages. The following bullets highlight the main findings of this research:
• The accident symbol was well understood and showed a benefit in the motorists’ ability to recall the situation in very limited viewing time situations.
• Researchers recommend using the Man Working figure without the diamond background outline as this had the best reaction time by study participants.
• Lane blocked symbols worked well in communicating lane conditions to drivers.
Presented at the 91st Annual Meeting of the Transportation Research Board, January 2012, Washington, D.C.