Is the Airport Symbol Sufficient to Convey Route Information?

Abstract

The silhouette of a jet aircraft that is used as an airport symbol on highway route markers was evaluated to determine the strength of its directional information when used with an arrow route marker and when used alone. Signs with the plane silhouette plus the route arrow were combined as described in the Manual of Uniform Traffic Control Devices; that is, no agreement between plane orientation and route direction was required. This produced signs with concordance, discordance, and orthogonal relationships between the plane orientation and the route direction. In addition, signs with the plane silhouette only (without a route arrow) were tested. Without prior instruction, the majority of the observers did not interpret the airport symbol as providing directional information without a route arrow. However, after instructions, the mean response time for signs of plane silhouettes alone (752 ms) was comparable to response times (765 ms) for signs with concordance between plane-silhouette orientation and route-arrow direction. Response times to signs with orthogonal and discordant relations between plane and arrow direction were significantly slower (834 ms and 865 ms, respectively).