A Proportion Based Format System for Freeway and Expressway Guide Signs

The Manual on Uniform Traffic Control Devices (MUTCD) has grown much more complex since 1961, the year that a section on signs for freeways and expressways was added to the manual. Yet that growth has been reflected primarily in the addition of more regulatory signs and a great deal of qualifying language. The actual standards for sign legibility and layout have changed little; however, the complexity of the roadway environments and the demand placed on the system has changed significantly. This paper builds upon previous work by the authors, which proposed similar formatting for conventional road guide signing. The intent of the system proposed in this new work is to improve the consistency and uniform readability of freeway and expressway guide signs based on defined proportions for key dimensions including: border, figure (legend and related graphics) and field relationship, and line space. The focus of this paper is to extend the principals of the proportion based system developed for the design of guide signs for conventional roads (MUTCD Chapter 2D) to include guidance for the design of guide signs on Freeways and Expressways (MUTCD Chapter 2E) and the associated guidance for sign layout in the FHWA Standard Highway Signs book. This design scheme is based on a foundation of proportional relationships that are made uniform for all common applications based on the common dimension, “X” of the height of the lead capital letter of the primary legend.