Pavement markings have a relatively short service life compared with that of many other roadway assets. In 2004, the Center for Transportation Research and Education (CTRE) at Iowa State University began working with the Iowa DOT to develop tools to manage the pavement markings and improve marking performance. Expectations were that the outcomes also would improve roadway safety.
Iowa DOT central and district staff now routinely use the tools developed by CTRE to monitor and manage pavement marking assets. Iowa DOT has established minimum retro-reflectivity standards of 150 millicandela (mcd) for white lines and 100 mcd for yellow lines based on the effects of pavement marking quality in reducing vehicle crashes.
Both Iowa DOT and Minnesota DOT have changed their pavement marking installation practices as a result of the research findings. The research showed that pavement grooving protected the markings from the wear of traffic and from winter maintenance operations and the potential savings ranged from $210 to $420 per 2 lane miles in a 3-year cycle.
From a safety perspective, the researchers documented a decrease in crashes with increased retro-reflectivity in longitudinal pavement markings. For example, on a two-lane rural road, the crash probability decreased by 2.5 percent when pavement marking retroreflectivity increased from 50 mcd to 200 mcd.