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Guidelines for Traffic Sign Symbols

In recent years, there has been a considerable interest in the influence of increasing numbers of older drivers on the highway system. Swanson Transportation Consultants Ltd. was engaged by the U.S. Federal Highway Administration to examine the design of traffic sign symbols for all drivers but, in particular, older drivers. The objectives were to evaluate the effectiveness of current symbols in the U.S. Manual on Uniform Traffic Control Devices (MUTCD). to recommend improvements to current symbols and to develop sign design guidelines. A two phase research study was conducted of the traffic sign symbols contained in the MUTCD involving six tests: comprehension, daytime legibility distance, legibility distance under night and night-with-glare conditions, glance legibility, reaction time, and conspicuity. The results of these studies served as the basis for recommended changes to current traffic sign symbols and the development of guidelines for their design. This paper will provide an overview of the study results but focuses on the design guidelines.