Sinusoidal Rumble Strips Safety Evaluation

This evaluation determined the change in crash frequency, type or severity associated with longitudinal sinusoidal rumble strips on rural two-lane undivided Minnesota roadways constructed between 2018 and 2022. Crash modification factors (CMFs) were estimated using cross-sectional analysis to compare crash experience of locations with sinusoidal rumble strips (i.e., centerline only, centerline and shoulder, or shoulder only) compared to roads with rectangular rumble strips. The cross-sectional analysis matched sites with sinusoidal and rectangular rumble strips using matched-pair comparisons. Negative binomial (NB) or Poisson log-linear regression models were used to model the crashes at all treatment and non-treatment sites. There was a total of approximately 327 miles of treated (i.e., centerline only, centerline and shoulder, or shoulder only sinusoidal rumble strips) and approximately 302 miles of untreated (i.e., centerline only, centerline and shoulder, or shoulder only rectangular rumble strips) on rural two-lane divided roads. Overall, the results of the models indicated no significant differences in crash rates between rural two-lane undivided roads with sinusoidal rumble strips, and rural two-lane undivided roads with rectangular rumble strips. The report is available electronically from the Minnesota DOT digital library at https://mdl.mndot.gov/items/202340