They are a vital safety feature on hundreds of miles of Minnesota roads and have saved many lives. Now transport chiefs are looking to make rumble strips less annoying for nearby residents.
Minnesota's Department of Transportation says it has received a "significant number of complaints" from landowners living near roads with centerline rumble strips, saying they are too noisy and can be heard more than 3,000 feet away.
That's according to this MnDOT report, which has revealed the results from tests it conducted in Polk County of quieter rumble strips that still do the job alerting drivers when they are veering over road boundaries.
Currently, 800 miles of Minnesota roads have the traditional rectangular rumble strips, but the study found that a "sine wave" shaped strip used in California produces as much noise inside the vehicle as the Minnesota design, but less sound outside of it.
This video shows a comparison between the two different strips:
Further testing of this strip will continue – mainly to figure out how wide they need to be on Minnesota roads and their effect on motorcycles and bicycles – but it looks as though MnDOT has settled on the new design.
They won't be installed everywhere – MnDOT notes they are expensive and some roads may not be wide enough – however they do plan on putting them into "noise-sensitive areas."
The Duluth News Tribune reported last year that MnDOT removed centerline rumble strips on Highway 61 in Lake and Cook Counties after a petition over the noise was signed by more than 300 people living in the area.
A year earlier, FOX 9 reported that residents of Chanhassen and Norwood-Young America had to keep their windows closed at times and found it difficult to have backyard conversations because nearby strips were causing sounds "like B-52 bombers."
According to KSTP, transportation department figures say centerline rumble strips have reduced crashes on two-lane rural roads by 9 percent after they were installed, resulting in a 12 percent drop in fatalities and injuries.
They also reduced the number of incidents where vehicles cross the centerline by 39 percent, the news station noted.