Minnesota Soybean Business

Whatabout roundabouts?

May-June 2019

With about 200 installed in Minnesota, roundabouts have become an increasingly popular intersection type among traffic engineers, communities and transportation officials. Roundabouts help contribute to better safety, traffic, fuel efficiency and air quality.

Compared to stop signs or stoplights, reports show roundabouts limit the amount and severity of crashes. A study by the Minnesota Department of Transportation (MnDOT) showed an 86 percent decrease in fatal crashes, an 83 percent reduction in life-altering injury crashes and a 42 percent drop in injury-crash rates at intersections.

“Because of the geometry of roundabouts, crashes are typically much less severe than those at stop signs or traffic lights,” says MnDOT Traffic Engineer Brett Paasch. “With the momentum of vehicles going in the same direction, roundabout crashes are more likely to only include property damage, rather than injuries.”

Paasch reports that roundabouts are typically able to handle traffic with less delay than most stop lights or signs.

“Generally, roundabouts works great for moderate-to-low volume trafific,” Paasch says. “We also look for intersections with relatively balanced legs to warrant the installation of a roundabout. If one of the roads has a much higher volume of traffic than the other, that’s not a great place for a roundabout.”

Another perk of roundabouts is that when they replace stoplights, the amount of idle time decreases, reducing vehicle emissions and fuel consumption by 30 percent or more.

Roundabouts are built for all types of vehicles, including farm equipment and large trucks. Roundabouts feature a truck apron, a raised section of concrete around the central island, which provides extra room for large vehicles to maneuver. The apron allows for the back wheels of an oversized vehicle to ride up onto to complete a turn.

MnDOT Project Manager Robert Jones has some tips for all drivers, including farmers, when navigating a roundabout at the same time as a large truck.

“In multi-lane roundabouts, give truck drivers room to drive through,” Jones says. “Roundabouts are designed so trucks don’t have to use both lanes, but if the truck driver strays a bit from their lane, it’s important that other vehicles have given the truck ample space to drive through.”

Jones also says that while truck drivers may wish roundabouts were larger, bigger doesn’t always mean better. A larger roundabout can lead to more safety issues.

Jones and Paasch note that several more roundabouts are currently in the works.

“At MnDOT, we like roundabouts because they save time, fuel, emissions and lives,” Paasch says. “They won’t be going away anytime soon.”

Navigating a roundabout

  • Slow down when approaching a roundabout. For multi-lane roundabouts, get into the appropriate lane.
  • Yield to pedestrians in the crosswalk.
  • Yield to vehicles already in the roundabout. Merge into the traffic fl ow when it is safe.
  • Continue through the roundabout until reaching the exit. Don’t stop or pass in a roundabout.
  • Exit the roundabout immediately if an emergency vehicle approaches, then pull over. Do not stop in the roundabout.
  • Yield to pedestrians in the crosswalk when exiting the roundabout.
  • Give large trucks extra space in a roundabout. Large trucks may straddle both lanes while driving through a multi-lane roundabout.


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