Response Time and Decision Accuracy for ‘No Turn on Red’ Signs

Abstract

‘No turn on red’ signs have been the subject of traffic research in recent years because they are violated at higher rates than other signs. One reason may be due to inadequate conspicuity. This study examined response times and decision accuracy (proportion correct) following glance exposure to three different ‘No Turn on Red’ signs. Two of the ‘No Turn on Red’ signs tested are currently being used on U.S. roadways in some jurisdictions; one contains only text and the other contains a red circle with text. These were compared to a third “new” sign (Prohibition Arrow and Text). The three signs and a no-sign condition (control) were embedded into 12 different traffic scenes. Each sign and scene condition was presented for a 1 s duration and then participants responded whether they could turn right in that particular scene or not (answering yes or no). The new (Prohibition Arrow and Text) sign condition had significantly faster response times compared to the other two signs. Accuracy was approximately 90% and did not differ among sign conditions. The no-sign condition was responded to significantly slower and less accurately than the sign conditions. The new (Prohibition Arrow and Text) sign yielded better performance than the other sign conditions in scenes rated as highly cluttered. Some explanations on why the new sign benefited decision times are discussed.