Comparison of Different Transverse Rumble Strip Patterns at Rural Stop-Controlled Intersections in Minnesota

Transverse rumble strips (TRS) provide a tactile and audible warning for drivers approaching an intersection and are used primarily to decrease crashes resulting from failure to yield. The objective of this study was to evaluate how TRS patterns affect behavior at rural stop-controlled intersections. A TRS design was selected based on the Minnesota (state in the midwestern U.S.) Department of Transportation’s current rumble strip depth/shape and panel locations. Four patterns representing variations of this design were developed and installed at rural intersections with stopping behavior concerns in St. Louis County, Minnesota. The patterns included two panels with six rumble strips each (two sites), two panels with 12 rumble strips each (two sites), three panels with six rumble strips each (one site), and three panels with 12 rumble strips each (two sites). Traffic volume, speed, and video data were collected 1 week before TRS installation and then 1 month and 9 months after installation. Evaluation metrics included average speed, percentage of vehicles traveling 45 mph or more upstream of the intersection, full/rolling stops, and late braking. Each pattern was assigned a qualitative score based on points assigned for each metric, and differences in metrics among the patterns were compared between the 1-month and 9-month-after periods. The three-panel/12-rumble strip pattern had the highest qualitative score (1.33). The second highest score was for the three-panel/six-rumble strip pattern (0.88). However, since this pattern was only installed at one site, this result should be interpreted with caution. The two-panel/12-rumble strip pattern had the lowest score (0.44).