Warning signs as countermeasures to camel-vehicle collisions in Saudi Arabia.

The camel-vehicle collision (CVC) problem has been increasing in Saudi Arabia and countermeasures are urgently needed to alleviate the heavy losses from such accidents. A research project was funded by the Saudi Arabian government to investigate the problem and to develop techniques to deal with it. Among the different techniques investigated were camel-crossing warning signs. In this study, seven camel-crossing warning signs were tested to determine if they would reduce the number of CVCs on rural roads. The measure of effectiveness utilized was the mean speed reduction of motorists passing such signs. In this paper, the experiments of warning sign testing are detailed, and the evaluation of the signs, based on the results of the testing experiments, is presented. Although most of the signs brought about significant reductions in mean speed, indicating statistical effectiveness, the speed reductions were not relatively large; they ranged from around 3 to about 7 km/h. Furthermore, statistical analysis was used to rank the signs according to their effectiveness. A triangular warning sign with a black camel silhouette and diamond reflective material (220 cm x 220 cm x 220 cm) is recommended in this study. This sign is similar to the standard warning sign used in Saudi Arabia except that it is twice the standard size and uses diamond reflective material.