Survey of State Practices for Prevention and Mitigation of Pavement Edge Drop-off During Design, Construction, and Maintenance

Pavement edge drop-offs (PEDO) are a safety concern which span multiple transportation organization’s levels (maintenance, safety, construction, design). PEDO is a vertical elevational difference between two adjacent roadway surfaces. It poses a potential safety problem when a vehicle strays from the travel lane due to driver inattention, distraction, or other driver error and encounters the drop-off. When a vehicle leaves the travel lane, the right wheels drop-off the edge of the roadway surface, with the normal reaction to attempt to return to the travel lane by over-correcting, with potential loss of vehicle control. Although it is generally accepted that significant edge drop-offs are a safety concern, the extent of the problem across the nation has not been fully explored since many agency guidelines related to shoulder maintenance or resurfacing improvements are not known. Presented is a synthesis of information from various states and provinces contacted to determine state of the practice and summarize guidelines for prevention and mitigation of edge drop-off during design, construction, and maintenance. Also covered are practices with regard to the analysis of safety data. This information is provided so that agencies can compare their practices with those of other agencies. It also provides information for agencies wanting to adopt or update guidelines and practices.