查看文章

The goal of this study was to evaluate the conspicuity, legibility, and effectiveness of symbolized pavement markings that are elongated (horizontal) versions of the post-mounted signs they complement. Towards this goal, a comprehensive literature and state-of-the-practice review was performed followed by a driving simulator evaluation and field evaluation of elongated pavement markings. Research shows that elongated pavement marking letters and arrows significantly improve recognition distance; however, the effect of elongated pavement marking signs has not been evaluated. Based on a comprehensive literature review and feedback from the Traffic Control Devices Pooled Fund Study members, speed limit (R2-1), curve (W1-2), and pedestrian crossing (W11-2) signs were chosen for the driving simulator evaluation. Results from the driving simulator evaluation indicate that recognition distance increased quadratically as elongation ratio increased. Data suggested an elongation ratio of 5: 1 provided maximum visibility distance for drivers. Driving simulator results also showed that operating speeds of drivers in conditions with elongated pavement marking signs complimenting post-mounted signs were similar or lower than operating speeds in locations with only post-mounted signs. The field evaluation was limited to speed limit and curve signs. Field evaluations were conducted in Kansas, Missouri and Wisconsin using the 5: 1 elongation ratio for speed and curve warning signs. Operating speed of free flowing vehicles was used as the measure of effectiveness and speed data were collected upstream of-, at-, and downstream of the …