Comprehension and Legibility of Evaluations of International and Domestic Nonstandard Symbol Signs, Phase Two

Traffic signs are an important communication tool used to convey regulatory, warning, and guidance information to road users. The process for understanding user requirements for a new sign is particularly important for symbol signs, which rely on a common non-verbal interpretation by a large and diverse population of drivers. If easily understood, symbol signs can be more effective than word message signs. In this study, researchers conducted 103 surveys to determine driver comprehension and legibility for multiple sign alternatives in nine sign message categories. The sign categories were: Alternate Merge, Bike Symbol, Grade Crossing (Crossbuck), Pedestrian Crossing, Toll Collection, Truck Rollover with Advisory Speed Limit, Trucks in Roundabouts, Walk Bikes and Weave. Based on the results of the comprehension and legibility testing, the research team provided recommendations on symbols that should be included in the next edition of the Manual on Uniform Traffic Control Devices (MUTCD).