Driver Understanding of Alternative Traffic Signs

Abstract

Traffic control devices are intended to promote safe and uniform operation of motorized and nonmotorized traffic using the roadway. Motorists rely on traffic control devices to provide information about traffic laws and regulations, to identify potential roadway hazards, and to provide information to help them find their desired destinations. However, traffic control devices serve little purpose if they are not understood by a significant proportion of the driving population. The findings and recommendations of a 5-year research study conducted by the Texas Transportation Institute to assess and improve motorist understanding of traffic control devices are presented. Phase I of the project was devoted to several evaluations of 52 devices, administered to 2,414 Texas drivers. Phase II of the project was devoted to the development and evaluation of alternative designs for 10 traffic signs identified in Phase I that exhibited potential for driver misunderstanding. The Phase II evaluations included four focus groups, an initial statewide survey of 747 Texas drivers, and a follow-up survey of 212 drivers. The results of all evaluations were analyzed to distinguish significant comprehension difficulties. Recommendations for each device were based on these results and include retaining the current standard design because of adequate comprehension levels, modifying the design or use of the device to increase comprehension levels, or conducting further research to better understand driver comprehension difficulties.

Comprehension and Training of International Road Signs

“…However, several had low comprehension levels, indicating that their associated safety message would not be adequately presented to drivers (Picha, Hawkins, Womack, & Rhodes, 1997). Numerous studies have found low comprehension levels for symbols (Caird, Wheat, McIntosh, & Dewar, 1997;Picha et al, 1997;Shinar et al, 2003). In order to improve the sign situation the design of symbols/signs should be based on iterative design principles together with input from samples of the target consumer.…”

Driver Behavior at Highway-Railroad Grade Crossings: A Literature Review from 1990-2006

“…Although the crossbuck and advance warning sign convey the message that a grade crossing is near, the driver action required and the location of the sign with respect to the grade crossing is not well understood (Bridwell, et al, 1993;Dolan, 1996;Fambro, et al, 1994;Picha, et al, 1997). This section addresses research conducted since the publication of that examined driver understanding of the signs at grade crossings and discusses proposed alternative sign systems to improve driver comprehension.…”

“…Several studies have examined driver attitudes towards grade crossings and driver comprehension of signs at grade crossings. The results generally show that drivers recognize the warning signs (Dolan, 1996;Global Exchange, 1994;Picha, et al, 1997). In one focus group, participants named the advance warning sign as the most familiar indication of a grade crossing followed by the crossbuck and pavement markings (Dolan, 1996), and participants in another focus group indicated that they considered crossbuck to be the basic marker identifying the location of railroad tracks (Global Exchange, 1994).…”

“…However, many drivers do not know where the signs are located relative to the grade crossing, that both the advance warning sign and crossbuck are used at active and passive crossings, or what driver action is required. Responses to a questionnaire examining driver understanding of the standard advance warning sign showed that although 81 percent of drivers could identify the sign when shown an image of it, 18 percent of drivers did not know where the sign was located with respect to the crossing (Picha, et al, 1997). Similarly, a survey conducted by Fambro, Schull, Noyce, and Rahman (1997), which tested driver understanding of traffic control devices at grade crossings and their responsibilities, found that 30 percent of the drivers did not know where the advance warning and crossbuck signs were located with respect to the crossing, 50 percent of drivers did not know that the advance warning sign was used at both active and passive crossings, and 34 percent did not know that the crossbuck was used at both crossings.…”

“…In particular, the presentation of supplementary signs for use in conjunction with the standard advance warning sign and crossbuck has received much interest. Picha, et al (1997) evaluated driver understanding for the standard advance warning sign when it was presented alone and with a supplementary plaque stating "500 ft." Two additional alternative sign systems for conveying the presence of a crossing were also evaluated as part of the study: a circular sign with an image of a black locomotive, and a circular sign with an image of a black locomotive with the text "500 ft" below the image. Participants completed a survey in which they were shown images of signs and asked to select the correct response.…”