Performance Evaluation of Pavement Markings Under Dry, Wet, and Rainy Conditions in the Field

The nighttime visibility of three types of pavement markings—a largebeaded permanent pavement marking and two types of patterned pavement marking tapes, one with high-index beads and the other with mixed high-index beads—was evaluated under dry, wet (just after rainfall), and simulated rain conditions (ongoing 1-in./h rainfall). The dependent measures were pavement-marking end-detection distance and retroreflectance. The experiment was conducted at the 3M Transportation Research Center in Cottage Grove, Minnesota. This facility features a level and straight roadway section where 1-in./h rainfall can be simulated. Eighteen subjects between the ages of 55 and 75 participated in the study. The participants drove an experimental vehicle on dry and wet test sections with the pavement-marking treatments. Participants noted the earliest point at which they were able to see the end of the right edge line pavement markings. The retroreflectance of each pavement-marking material was also measured with three handheld retroreflectometers under the three weather conditions, according to ASTM E1710 (dry), ASTM E2177 (wet recovery), and ASTM E2176 (continuous wetting) standards. In terms of end-detection distances, the patterned tape with mixed high-index beads performed best under all three weather conditions. The paint and large-bead pavement markings were comparable to the tape with high-index beads under wet and rainy conditions. Under dry conditions, paint and large-bead pavement markings performed the worst. The detection distances seemed to strongly correlate with the standard retroreflectances only if the retroreflectance data from the corresponding test method are used.