Since the roundabout was installed five months ago at College Street and 11th Avenue, the average vehicle’s wait time at the intersection has shrunk significantly, a study has found.
“There’s a huge reduction in delay during the peak traffic period from 5 to 5:15 p.m.,” city engineer Brian Heaston said.
After the roundabout opened in August, Montana State University’s Western Transportation Institute took video surveillance of the intersection.
The institute compared traffic counts for the roundabout to counts collected in 2009, when the intersection had a four-way stop. Data was collected only for northbound traffic.
When the intersection had a four-way stop, 133 vehicles arrived during the peak period with an average estimated delay of 153 seconds per vehicle.
With the roundabout, 146 northbound vehicles were counted during the peak period with an average delay of 20 seconds.
So, the roundabout has saved the average vehicle 133 seconds — more than 2 minutes, the study found.
Not only has the roundabout made the intersection faster to drive through, but there have also been fewer crashes along West College Street since it was installed, city officials say.
When the intersection was a four-way stop, cars backed up along West College Street waiting for their turn to go.
From August to January 2009, there were 10 crashes on West College Street, mostly from drivers unable to stop or sliding into the rear end of another backed-up car, according to Bozeman Police Deputy Chief Rich McLane.
During the same five-month time period since the roundabout went in, there was one crash along the road.
At the intersection itself, there have been four vehicle crashes since the roundabout was installed, McLane said. That’s the same number that occurred in 2009, when there was a four-way stop.
Of the four crashes since August, two resulted from drivers traveling too fast and not being able to stop for a vehicle in front of them. One involved a hit-and-run where the vehicle was driving the wrong way and struck a bicyclist. Finally, a vehicle hit a crosswalk sign that had to be replaced.
McLane said police have not received any complaints about pedestrian safety since the roundabout opened.
Amanda Ricker can be reached at aricker@dailychronicle.com or 582-2628.
crankycowdog posted at 7:28 am on Fri, Jan 27, 2012.
I like the roundabout. As expected, the learning curve is taking time for local drivers, a group that seems to be getting worse in their overall driving behavior rather than better. So the fact that they are starting to figure out the roundabout is a bit of miracle. Maybe we need more of these.
cowboyup posted at 1:14 pm on Thu, Jan 26, 2012.
It's a Socialist plot. Republicans go in and they come out Democrats.
Montaska posted at 11:55 am on Thu, Jan 26, 2012.
Frostycakes! My dear Frostycakes! Why do you have to signal when entering a roundabout if you can only go around it to the right?
And, although I agree with using the signal when exiting, I'm not trusting somebody's blinker enough to allow me to pull out in front.
frostycakes posted at 9:04 am on Thu, Jan 26, 2012.
Speaking as someone who lived in an area with a ton of roundabouts before: No one, I repeat, NO ONE signals when entering/leaving them, especially the larger, multi-laned ones. What on earth is so complicated about getting in, going around, and getting out? I can't count how many times I've gotten stuck behind overcautious people at that intersection who seem to think that they can't enter the roundabout when the only car in it is on the opposite side. Maybe this'll provide the impetus for drivers in this town to stop driving 5-10mph UNDER the speed limit too, but I guess all a man can do is dream.
MTDavo posted at 1:04 am on Thu, Jan 26, 2012.
Yes, it's amazing! Less wait time, safer intersections, and now we find ourselves knowing what the rest of the world has known for a long, long time. Roundabouts work! Build more and make Bozeman safer and more convenient.
antishenanigans posted at 9:40 pm on Wed, Jan 25, 2012.
I will admit that I was completely wrong about the effectiveness of the roundabout. It has expedited traffic dramatically; most people know how to enter and exit them; and I have yet to see an accident. And, yes, aggressive drivers are rewarded. It's the hesitant, passive drivers that cause traffic. Yield to those that are IN the roundabout. Otherwise, get in and (signal) get out.
cowboyup posted at 10:20 am on Wed, Jan 25, 2012.
Told ya so..
flipflops posted at 9:44 am on Wed, Jan 25, 2012.
BznRes, was it too hard to find the roundabout page on the MONTANA DOT? Because it took me three seconds to Google and click on the link.
http://www.mdt.mt.gov/travinfo/roundabouts/
"7.Look for your street, use your right-turn signal and exit the roundabout."
BCMontana posted at 9:31 am on Wed, Jan 25, 2012.
If you're the poor sap coming from the east at 5:10PM, you can get stuck there for a very long time. Basically, anytime there is a line of cars to your left, you're screwed.
As BznRes correctly pointed out, this would not be as much of a problem if people signaled, but few do. Also, aggressive drivers are rewarded in this roundabout.
My personal experience has been about the same level of frustration as when it was a four-way. I avoid that intersection at certain times of the day just as I always did.
On the plus side, we are told it was a cheaper option than a signal, and I'm not sure a signal would have moved traffic any better. The biggest problem is there are too many vehicles at certain times for a single-lane intersection.
BznRes posted at 9:13 am on Wed, Jan 25, 2012.
Why don't people signal when exiting the round-about?
I avoid this intersection as much as possible. I find it frustrating when I'm waiting to enter and then a car zips out of the round-about without signaling. Had they signaled I could have made it in. It's still an intersection and like all intersections, you must signal when changing lanes. I've even seen police not signal when exiting. Bozeman drivers are among the worst and need to be educated. NV DOT provides easy to follow instructions for round-about laws (eg. "Use your turn signal to indicate when exiting.") http://www.nevadadot.com/safety/roundabout/driving.aspx
pragmatic posted at 8:16 am on Wed, Jan 25, 2012.
Four way stops are ridiculous, especially in newly developed areas where the cost of installing a roundabout is substantially less than retrofitting. Four way stops for existing high volume intersections are like putting a band-aid on a broken leg; the cost of treating the problem will eventually be aligned with the size of the problem.
Roundabouts are not perfect for all situations, but in this case I feel it was a good investment and it makes this intersection flow smoothly.
DR posted at 12:44 am on Wed, Jan 25, 2012.
Oh, but I thought roundabouts don't work and people get confused and wreck more often! Great job by the city. Roundabouts work and they will continue to do so. Billings and Bozeman are on a good path.