ATSSA: Improving Driver Behavior with Infrastructure Safety Countermeasures

6 Improving Driver Behavior with Infrastructure Safety Countermeasures Figure 7. A Wrong Way sign with LED enhancement (Image: Traffic & Parking Control Co. Inc. (TAPCO)) Figure 6. Post-mounted chevrons in a curve, Route 218, King George County, Va. The school-area sign (right) warns of pedestrians in the area (Image: James Scott Baron, ATSSA) Figure 8. Another use of a Wrong Way sign at the foot of a freeway ramp (Image: TAPCO) chevron signs also provide illumination in low-light driving conditions for curves that do not have roadway lighting. This guidance encourages a speed reduction that will assist the driver to keep the vehicle in the lane and not depart the roadway. Regulatory signs convey requirements to which drivers must adhere. Stop and Yield signs, for example, help drivers to understand where they must share the same roadway space with other road users. Orderly movement of drivers through intersections reduces the potential for crashes. Speed limit signs eliminate the need for drivers to make decisions about an appropriate speed for the given roadway geometry and volume conditions. These signs promote uniformity in driving speeds and can prevent drivers from responding inappropriately to the given conditions. Additionally, One- Way and Wrong Way signs provide positive guidance about the correct direction of travel along a roadway or a particular segment of the roadway. To improve driver behavior and help mitigate wrong-way- driving incidents, some of the general principles for sizing and installing signs must be modified to be most effective. Mounting regulatory signs (such as Wrong Way and Do Not Enter) at a height of 3 feet, rather than the typical 5 feet in rural areas and 7 feet in urban areas, makes them more visible at night, because they are more directly in the path of a vehicle’s headlights. This lower height also makes the signs more visible to impaired and older drivers, who tend to look for visual cues from the pavement area. In using this signage modification, the California Department of Transportation noted that wrong-way-driving incidents decreased from 50 to 60 per month to two to six per month at some ramps that were notable for these incidents. Also, angling these signs toward the direction that the wrong-way driver is entering the ramp or roadway and installing signs on both sides of the roadway further increase the opportunity to positively affect driver behavior and prevent crashes. Other means to increase the visibility of these signs at night are red retroreflective strips on the signposts and light- emitting diodes (LEDs) around the sign edges. These two features alone make the sign more visible from a greater distance, before the vehicle headlights illuminate the sign’s retroreflective message. When the Texas Department of Transportation implemented flashing LED signs at 29 exit ramps along a 15-mile highway corridor in 2012, wrong-way-driving incidents decreased by approximately 30 percent.