Truck-Mounted Changeable Message Signs for Work Zone Operations

Truck-mounted changeable message signs (TMCMSs) are desirable for scheduled and unscheduled short-duration work operations to inform drivers of unexpected conditions. Temporary traffic control for short-duration operations has been limited traditionally to arrow boards and static warning messages mounted to the work vehicle. With advances in technology, TMCMSs can fill a gap and provide drivers with better information about short operations and required actions by the driver. Through a study in a human factors laboratory, researchers evaluated message designs that incorporated text and graphic alternatives to warn drivers about accidents, work zone areas, and lane closures. In this study, researchers determined many key points about motorist interpretations of TMCMS symbols and text messages. The study found that (a) the accident symbol was well understood and enhanced motorists’ abilities to recall the situation during limited viewing times, (b) the sign with the “Man Working” figure without the diamond background outline was recommended because it elicited the best reaction time by study participants, and (c) the lane-blocked symbols worked well to communicate lane conditions to drivers.