Traffic flow impressive, but two-lane intersection still creating confusion
One year after winning an engineering award, Forest Lake’s downtown roundabout will be restructured. Minnesota Department of Transportation officials presented at last week’s City Council workshop a plan to restripe the city’s main intersection into a one-lane circle.
The current two-lane model has succeeded in moving traffic swiftly and reducing serious accidents, but also continues to cause confusion that leads to fender-benders and close calls.
MnDOT East Area Manager Adam Josephson said the agency has created a large amount of roundabouts in the past five years and regularly monitors their performance.
“Roundabouts have kind of been a learning process,” he said.
According to MnDOT data, the Broadway Avenue-Highway 61 intersection saw 18 accidents from 2007-2009, with seven involving injuries. The roundabout opened in 2010. There were 25 accidents from 2011-2012, but only three involved injuries.
Most collisions result from one of two driver errors: drivers in the outside lane attempting to continue through the roundabout, and drivers entering the roundabout in the outside lane failing to yield to traffic exiting from the inside lane.
“At the present time we want to accommodate the traffic there and do it in as simple a way as we can,” Josephson said. “A single-lane roundabout is as simple as you can get. It’s a better way to handle the current traffic.
“This one is working well, but we think it can work a little better than it is.”
The double-lane roundabout was built to handle traffic volume projected in 2030. Re-striping it to a single lane should reduce accidents while still moving traffic faster than a signalized intersection, Josephson said. Unlike a straight road, a two-lane roundabout does not handle double the volume of a single-lane version.
“Roundabouts are kind of interesting in that capacity is very much driven by the time it takes for people to realize they can move into the roundabout,” Josephson said. “When there are two lanes, it takes a little longer to decide.”
The restriping cost is minimal and will be covered by MnDOT, Josephson said. He expects the work to be scheduled for
August and take no more than a couple days. The curbs will remain in place so the roundabout can be restriped to two lanes once traffic volume demands it.
Turn by turn
MnDOT’s plan includes dedicated right-turn-only lanes that sweep traffic outside the roundabout in two locations: turning south onto Highway 61 from eastbound Broadway Avenue and turning west onto Broadway Avenue from southbound Highway 61.
Drivers entering the roundabout from the south and east will funnel through one lane and can either turn right or continue through the roundabout.
Though the city bore the bulk of the original construction bill, restriping falls on MnDOT under a maintenance agreement. The intersection is unique in that different roundabout legs are owned by the state, county and city.
The City Council seemed supportive of the plan as presented, City Administrator Aaron Parrish said.
“Like everything, this was a good opportunity to reflect on what’s working and what’s not,” he said. “It’s encouraging about how it’s performing, moving a higher volume than what was anticipated. From that perspective, this represents a nice opportunity to enhance what’s happening there.”