Jul. 19—JAMESTOWN — A planned roundabout in Jamestown is expected to promote lower speeds coming into an intersection which typically results in a less severe crash, according to David Finley, assistant communications director for the North Dakota Department of Transportation.
“A roundabout has less conflict points than a traditional intersection and eliminates all crossing conflict points, which eliminates angle or T-bone crashes,” Finley said in an email to The Jamestown Sun.
The NDDOT selected the roundabout option for the U.S. Highway 52 and 10th Street Southeast intersection in Jamestown for improvements to U.S. Highway 52 from 7th Street Southeast on 1st Avenue South to 4th Avenue Southwest on Business Loop West. The NDDOT also selected a five-lane road with a two-way left-turn for Business Loop West, which is similar to the existing road.
A roundabout is a circular intersection where motorists travel counterclockwise around a center island. Motorists entering the roundabout must yield to traffic inside the circular intersection. Exiting the roundabout requires a right-hand turn.
The benefits of a roundabout include the elimination of high-speed traffic crashes, improved traffic flow, increased traffic capacity, ability to accommodate vehicles and trucks of all sizes and increased safety for all travelers, according to the NDDOT’s website.
The NDDOT project includes reconstructing the U.S. Highway 52 and 10th Street Southeast intersection and Business Loop West from 4th Avenue Southwest to 10th Street Southeast, replacing two bridges on Business Loop West and restriping 1st Avenue South from 7th to 10th Street Southeast to help match the configuration of the Road Diet project further north in the downtown area.
“We will end up being a little safer but also we will have a much better flow of traffic,” Mayor Dwaine Heinrich said, referring to the planned roundabout in Jamestown.
The purpose of the project is to address bridge and pavement condition, vehicular traffic operations and sidewalks for bicyclists or individuals who walk along and adjacent to the U.S. Highway 52 corridor in Jamestown from 7th Street to 4th Avenue Southwest, The Jamestown Sun reported in February.
Construction on the project is scheduled for summer 2027.
The estimated cost is nearly $9.2 million for the roundabout and about $6.5 million for the five-lane road with a two-way left-turn lane, The Jamestown Sun reported in February.
“There is no local share in this project,” Heinrich said.
Finley said the NDDOT will need temporary construction easements and a permanent right of way throughout the Business Loop reconstruction project.
Roundabouts have no traffic signals or stop signs and can continue to operate in a power outage.
“There is no signal equipment to maintain,” Finley said.
Finley also said roundabouts create “aesthetically pleasing” intersections that can be used as a gateway to a community.
Statistics for total crashes from Vision Zero North Dakota show 82 crashes have occurred at the U.S. Highway 52 and 10th Street Southeast intersection over a 10-year span from June 1, 2015, to May 31, 2025.
No fatal or incapacitating crashes have occurred at the intersection. The intersection has had five non-incapacitating injury crashes, 12 crashes with possible injury and 65 crashes that damaged property only, according to Vision Zero.
The most common collision at the intersection is rear-end. There were 58 rear-end collisions at the intersection, followed by 14 sideswipe collisions with vehicles traveling in the same direction, seven single-vehicle collisions, two angle collisions and one left-turn collision, according to Vision Zero.
Severe injury and fatal crashes were reduced by 59% and the crash rate decreased by 33% at roundabout intersections in North Dakota, according to an NDDOT traffic study completed in 2024. Total crashes per year were reduced by 36%.
The traffic study examined the safety performance of 12 roundabouts in the North Dakota transportation system by comparing the before-and-after-completion crash rates and severity. The study compiled before-and-after crash data at the roundabouts through June 30, 2023.
The study shows a decrease in the proportion of rear-end collisions, angle crashes and single-vehicle crashes at roundabout intersections.
The proportion of rear-end collisions was reduced by 22% at roundabout intersections.
Angle crashes were reduced by 16% at roundabout intersections.
Prior to the installation of roundabouts, angle crashes were more of a T-bone crash, the study says. After installing roundabouts, angle crashes consisted more of a merging crash between a vehicle entering the roundabout and a vehicle already within the circular intersection.
Single-vehicle crashes increased by 55% after installing roundabouts.
After the installation of roundabouts, the study shows single-vehicle crashes involved:
* 28% overturning or shifting load when circulating within the roundabout.
* 21% approaching the roundabout and going straight into the center island.
* 15% losing control when approaching the roundabout and going into the near right corner.
* 12% losing control while navigating the roundabout and going into the far right corner.
* 9% approaching the roundabout and hitting the median splitter island curb.
* 15% other miscellaneous events.
The proportion of property-damage-only crashes increased by 15%.
“This is a good thing as property-damage-only is the least severe category,” the study says.
One fatal crash was reported at a roundabout. The fatal crash involved one vehicle that was approaching a roundabout, crossed the median splitter island and hit another vehicle head-on.
Five incapacitating injury crashes occurred at roundabouts. Two involved DUI drivers going straight into the center island, one involved a truck that entered the roundabout at 60 mph and went into the far right corner, one invovling a motorcycle that lost control when exiting the roundabout, and another involved a motorcycle that hit an electric bicycle in a crosswalk.
The total number of crashes per year decreased by 59% after a roundabout was installed in 2016 at the intersection at U.S. Highways 52/281 and North Dakota Highway 200 in Carrington, according to the study. The total number of crashes decreased from 2.6 per year at the intersection to 1.08 per year at the roundabout.
The average crash rate was at 0.41 per 1 million entering vehicles at the Carrington roundabout after it was installed, a decrease of 59% from 1 per 1 million entering vehicles before the roundabout was installed.
A fatal or incapacitating crash has not occurred since the roundabout was installed. Before the roundabout, the intersection had 0.2 fatal or incapacitating crashes per year.
No angle collisions have occurred since the roundabout was installed. No sideswipe collisions with both vehicles going the same direction or left-turn collisions have occurred as well. The roundabout had one rear-end collision.
Before the roundabout was installed, the intersection had six angle collisions, four sideswipe collisions with both vehicles going the same direction and one each for rear-end, left-turn and other collisions.
The roundabout intersection had one crash that resulted in a non-incapacitating injury and six that only damaged property. Before the roundabout was installed, the intersection had one crash that resulted in an incapacitating injury, two with possible injuries and 10 that damaged property only.