Center turn lane

Mayor’s memo: The benefits of three-lane roads

Sometimes, three really is better than four. Three-lane roadways have many benefits over their four-lane cousins and are a good option when daily traffic volumes total 15,000 vehicles or less. Three lanes promote traffic calming by reducing speeding. Overall, safety improves. Studies show accident rates decrease. With left-turning vehicles removed from the driving lane and paths, rear-end crashes are reduced by around 20 – 45 percent.

With fewer lanes to cross, pedestrians have safer and more comfortable experiences crossing streets. A three-lane roadway creates a larger buffer between the sidewalk and moving traffic. Bicyclists gain a dedicated space for a bike lane or shoulder on both sides of the road.

We have experience with this kind of configuration in Bloomington. A three-lane roadway is not just about accommodating bicycles. That’s a secondary outcome. This is primarily about safety. People benefit when we move vehicles away from the curbside and sidewalk.

“Over the past decade, the City has converted more than 10 miles of four-lane, undivided roadways to three-lane, cross-sections with very positive results,” Civil Engineer Amy Marohn said. “We hear from pedestrians that they feel more comfortable walking on sidewalks with separation from vehicles. The before and after data we have collected shows speeding is reduced on each of these roadways.”