Evaluation of Adding Distance Information to Mainline Specific Service (Logo) Signs

About the report:

Specific service (or logo) signs provide information on attractions, camping, lodging, food, and gas services on the mainline of limited access highways in advance of the interchange that provides access to the services. At present, to ascertain the distance to a particular establishment, motorists depart from the mainline and read the distance on the logo signs on the ramps. Through a request from a state senator, the Virginia Department of Transportation (VDOT) was asked to consider adding distance information to mainline logo signs. The contention was that providing such information could help drivers decide whether to take a specific exit and thus avoid unnecessary weaving maneuvers if they deemed the service to be too far from the exit. Although there were potential benefits of this concept, there were concerns about its implementation--notably, whether the distance information could be easily read at freeway speeds. The purpose of this study was to determine the effectiveness or usefulness of adding distance information on mainline logo signs. The scope of the study was limited to a pilot study of adding distance information on mainline logo signs at three interchanges in Virginia. Because such information is not covered in the Manual on Uniform Traffic Control Devices (MUTCD), VDOT requested, and the Federal Highway Administration granted, permission to experiment with these signs. Distance information was added to existing logo signs at the three interchanges in the space available under the logo panels. The study examined legibility, motorist opinions, and crash history related to adding the distance information. The results of the study indicated that the legibility distance for the added information on the mainline logo signs was adequate in that it exceeded the rule of thumb of 40 feet/inch of letter height. Most legibility study participants found the distance information easy to read, although some found the information "cramped" on the signs. Most respondents to the motorist opinion survey found the signs "OK" or "easy to read" and the distance information useful. The presence of the distance information on the mainline logo signs did not affect the number of crashes at the sites used in the pilot study. The cost of replacing existing mainline logo signs statewide with new larger signs that would include distance information is estimated at $10.5 million. Additional costs to replace the sign structures to accommodate the larger signs might be substantial. As the primary benefit of adding distance information to mainline logo signs is motorist convenience, the required expenditure may be designated a low priority.

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