Daytime effects of raised pavement markers on horizontal curves

A large number of vehicle crashes occur every year on the horizontal curves found on many of America's rural two-lane highways. Of these, a significant number can be attributed to the encroachment of a vehicle into the opposing lane of traffic. While multiple factors may contribute in forming these hazardous road segments, most are not corrected due to economic considerations. The purpose of this study is to note the driver response to the application of raised pavement markers by measuring the changes in speed and encroachment distance after varying the spacing intervals of these markers. All data was collected in dry, daylight conditions and thereby testing the "rumble effect" of the markers rather than their reflective delineation qualities. It is found here that daytime encroachment levels can be significantly reduced by an optimal marker spacing (40 feet) though operating speeds are generally not affected.