Rumble strips among features reducing number of serious car crashes in South Dakota

Sam Fosness, The Daily Republic, Mitchell, S.D.
·3 min read

Aug. 25—MITCHELL — South Dakota has seen a steady decline in serious crashes over the past five years, and officials with the state's Department of Transportation say the installation of road safety features has been a key contributor.

In 2015, 803 serious crashes were recorded in the state. Fast forward to 2021, the number of serious crashes fell to 495, marking a significant reduction.

What's behind the drop in serious vehicle crashes? Mike Behmen, director of planning and engineering with SDDOT, pointed to the increase in rumble strips and a new surface treatment that have been installed into more state highways and interstates as key contributors to the reduction.

Rumble strips are grooved lines carved out of roads that are typically installed along the shoulders and centerlines of highways and interstates. The strips then vibrate vehicles when driven onto them, alerting drivers they are crossing traffic lines.

This year, the DOT added centerline rumble strips to 350 miles of roads around the state.

"There are things we are putting into the pavement and the system to help those behavioral aspects. If an individual is crossing the center line, the rumble strips are effective at giving them a warning that, 'Hey, you need to get back over to your lane,'" Behm said during the July DOT meeting in Mitchell.

Center line rumble strips have led to a reduction in head on collisions by 62% since being built into the roads, Behm said. The state has seen a 20% reduction in fatal crashes on roads that have implemented shoulder rumble strips.

"While 20% may not seem like much, our number one fatal crash in South Dakota is a single-vehicle running off the road," Behm said.

Another safety feature the SDDOT has implemented into roads is a high friction surface treatment, which helps icy roads become more skid-resistant during the winter elements. According to Behm, the surface treatment has led to an 80% reduction in crashes on roads where the treatment is applied.

"It's a very expensive technique, but it works very well," Behm said.

While fatal crashes dipped in 2019 to 102, it jumped back up in 2020 to 141, according to the South Dakota Department of Public Safety's data. The uptick in fatal crashes from 2019 to 2020 marked a 38% increase, which was followed by a slight drop in 2020 with 121 fatal crashes.

Among the counties that saw a high number of fatalities in 2020 were Pennington and Lawrence counties, which play host each year to the Sturgis Motorcycle Rally, an event that draws over 500,000 people to the West River cities.

However, it was Minnehaha County — which holds Sioux Falls — that recorded the most fatalities in 2020. Data from the state Department Of Public Safety showed Minnehaha County had 20 fatal crashes in 2020, double the amount Pennington and Lawrence counties had in 2020. The Mitchell area had just one fatal crash in 2020, according to the state Department of Public Safety.

"In 2019, we had 102 fatal crashes. That's 102 too many, but it's still one of the lowest on records," said Mike Behm, director of planning and engineering with SDDOT. "Speeding, alcohol and behavioral elements caused a lot of those."