Pavement markings play one of the most important safety functions on our roads. They are widely accepted as being beneficial to drivers in that they communicate the intended travel path for short-range operations and the roadway alignment for long-range delineation. To ensure consistent application of pavement markings, their characteristics and warranting criteria are described in the Manual on Uniform Traffic Control Devices (MUTCD)(1), setting national standards on their application.
Despite the national pavement marking standards described in the MUTCD, according to a recent American Association of State Highway and Transportation Officials (AASHTO) report, every 21 minutes a highway death occurs as a result of a lane departure. In total, that is over 25,000 fatalities per year, or almost 60 percent of the nation’s highway fatalities. AASHTO has developed a Strategic Highway Safety Plan that is designed to reduce these numbers (2). The very first objective of the AASHTO Safety Plan is to keep vehicles in their lanes and on the road.
The AASHTO Safety Plan includes a list of 22 goals to reduce highway fatalities. Various states around the country that have implemented the AASHTO Safety Plan have reported successes. . For instance, for the last three years, the Missouri Department of Transportation has focused on lane departure countermeasures. They have implemented the following countermeasures, which have led to a 25 percent reduction in lane departure fatalities from 2005 to 2007:
- edge lines and centerlines on all major highways, as well as minor highways with a history of crashes;
- 6-inch pavement marking edge lines and skip lines on all major highways;
- 4-foot shoulders on major highways;
- guardrail and median barriers on all major highways; and
- signing improvements.
AASHTO's first objective—keeping drivers on the road—appears simple enough. However, the safety potential of the objective is largely unknown. Surprisingly, there is an apparent lack of information concerning the most effective manner for keeping drivers on the road. Obviously, pavement markings are a big part of the equation. Although other safety treatments can also be used to keep drivers on the road, this paper is exclusively dedicated to pavement markings and their potential contribution towards increasing highway safety.