It’s often more difficult for motorists to see road edge-lines and centerlines on rainy nights, especially in rural areas with limited lighting.
However, while the reflectivity of pavement marking materials has improved in recent years, transportation agencies have lacked the right data to establish performance standards for wet, night-time visibility. A recent effort by MnDOT and the Minnesota Local Road Research Board aimed to address this.
The Pavement Markings – Wet Retroreflectivity Standards research project determined driver visibility needs and made pavement marking performance recommendations for wet, night-time conditions. The American Association of State Highway and Transportation Officials took notice, honoring the project with a Sweet Sixteen award as one of the nation’s top high-value research studies chosen by state DOT research directors.
Led by Ethan Peterson, Office of Traffic Engineering, and Adam Pike, Texas A&M Transportation Institute, the research team gathered data from existing studies and conducted pavement marking wet-night visibility tests with 43 Minnesota drivers to identify the amount of reflectivity needed for adequate visibility in wet-night conditions. Minimum levels required for both new installation and ongoing performance are now included in MnDOT’s standard specification for roadway pavement markings.
Future research will examine how long new pavement markings installed on targeted corridors hold up before reaching the minimum performance standard.
MnDOT staff were invited to speak about the pavement markings project at AASHTO’s recent virtual 2021 National Research Advisory Committee meeting, with Peterson pre-recording a short presentation played during the virtual event. In addition to presentations at two Roads & Bridges magazine webinars, staff involved will also present at the January 2022 Transportation Research Board annual meeting.