All about roundabouts | BrainerdDispatch.com | Brainerd, Minnesota

All about roundabouts

Posted: October 12, 2012 - 9:32pm
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Round and round they go, the city of Brainerd is about ready to introduce drivers and the community to roundabouts following the completion of the College Drive project, tentatively set for Oct. 26.

But why roundabouts? Brainerd City Engineer Jeff Hulsether said the decision was based primarily on safety.

“The arguments in favor of roundabouts are so overwhelming,” said Hulsether about bringing roundabouts to the area. “The safety, capacity and access provided by roundabouts was the perfect solution on College Drive and is being found to be the right solution in communities all over the state.

“As of last fall, there were over 180 roundabouts either constructed, being constructed, designed, planned or considered and that number will continue to grow.

“They will become very commonplace and more the norm than the exception.”

Hulsether added that concerns from citizens are understandable, and his biggest concern will be with the first snowfall as discussions about plowing have been brought up.

Hulsether gave his own advice for anyone hesitant to go through the new road additions.

“My advice for driving roundabouts is to simply slow down and follow the rules,” he said, adding the city is planning a ribbon cutting at 10 a.m. on Oct. 26 on the bridge deck. “First, before entering the roundabout be aware of the lane assignments which are the same as any other four lane road. If you plan to turn left or make a u-turn you should be in the left lane. If you plan to make a right turn, use the right lane. If you plan to go straight, you can use either lane. Next, watch for pedestrians crossing at the roundabouts and yield to anyone in the roundabout to your left.”

For further explanation, the Dispatch spoke with Andrew Plowman, transportation project manager and roundabout expert at WSB and Associates, Inc., the city’s consultant on the College Drive project, Plowman included the following explanations:

What is a roundabout?

According to Plowman, it’s a circulatory intersection in which motorists in the circulating lane have the right of way over entering vehicles.

Driving Tips

1. Yield to pedestrians in the crosswalk.

2. Choose the correct lane approaching the roundabout. Left lane is for left turners, right lane is for right turners. The through movement can be made from both lanes.

3. Yield to vehicles in the circulating lanes (note, there may be more than one circulating lane). Yield does not mean merge. When you see a gap, you may enter the roundabout.

4. Do not stop in the circulating lane. Do not change lanes within the circle.

5. If an emergency vehicle is near and you are within the circulatory lanes, continue through the roundabout and pull over once you exit the roundabout provided there is adequate space for the emergency vehicle to pass you.

6. Give large trucks adequate space to maneuver through the roundabout. The roundabouts include a truck apron (red concrete area), adjacent to the central island, which allows trucks to track upon when maneuvering through the roundabout. The truck apron is not to be used by passenger vehicles.

7. All traffic should travel counter-clockwise through the roundabout. It is dangerous to travel through in the opposite direction.

8. Travel cautiously through the roundabout. You may know how to travel through the roundabout, but other motorists might have trouble the first few times.

9. Keep in mind, roundabouts provide a great opportunity to make a U-turn to access areas that may be blocked by a median. Be sure to enter the left lane for this move, and go all the way around the roundabout when making the U-turn.

10. Never change lanes within the roundabout and do not make a left turn from the right lane. The interior motorist may be making the thru movement.

Although over 3,400 roundabouts have been constructed in the United States since 1990, much of the public still has a difficult time embracing the benefits of the relatively new type of intersection. Below is a list of some of the key benefits to roundabouts over other types of intersection control.

Roundabout Benefits:

• Improves safety — Intersections converted to roundabouts from a stop controlled or signalized configuration have shown the following reduction in collisions:

• A 37 percent reduction in overall collisions

• A 73 percent reduction in collisions which result in an injury.

• A 90 percent reduction in collisions which result in fatality.

The reasons for the improved safety include low travel speeds and reduced conflict points. Drivers are required to slow down prior to entering the roundabout, simply due to the geometry. Typically, speeds entering the roundabout are between 15 and 20 mph.

The reasons for the improved safety are the following:

• Low Travel Speeds – drivers are required to slow down prior to entering the roundabout due to the geometry of the roundabout. Typically, speeds entering the roundabout are between 15 and 20 mph. The collisions that may occur are sideswipe type crashes that are not severe like 90 degree (T-bone) type crashes that are typical at signalized and stop controlled intersections

• Reduced Conflict Points – There are 32 potential conflict points at a standard signalized or stop controlled intersection. The corresponding number of conflict points at a roundabout is eight. In addition, there are no left turn conflict points as all traffic is traversing in the same direction around the roundabout.

• Reduce Delay, Improve Traffic Flow: Roundabouts promote a continuous flow of traffic. At a signal, drivers are required to wait for a green light to enter the intersection. At a stop controlled intersection, traffic is required to come to a complete stop whereas traffic is only required to yield at a roundabout. At a side-street stop controlled intersection, motorists are required to find a gap which is more difficult with the higher speeds than what exists at a roundabout. This results in some motorists taking chances to enter the intersection.

Studies by Kansas State University measured traffic flow at intersections before and after conversion to roundabouts. In each case, installing a roundabout led to a 20 percent reduction in delays.

• Less Right of Way Required: Although a roundabout may require more land at the intersection itself than a signalized intersection, roundabouts often require less space leading to the intersection. This is because signalized and stop controlled intersections require long storage space for left and right turn lanes.

• Reduction in Emissions and Fuel Consumption: Due to the continuous flow and decrease in vehicle idling, roundabouts are shown to reduce carbon monoxide and carbon dioxide emissions as well creating a reduction in fuel consumption.

• Aesthetics: The central island and splitter islands allow for landscaping. This provides the opportunity to create a gateway for a community. The landscaping can also create an aesthetic division between commercial and residential areas.

Currently, the roundabouts are open to traffic, to some extent. Much of the landscaping will be placed in the spring, which will cause some lane closures for the contractor to access the central island and splitter islands.

Additional sources regarding roundabouts can be found at the following websites:

www.dot.state.mn.us/research/how-about-a-roundabout-video+brochure.html

www.dot.state.mn.us/roundabouts/

www.co.washington.mn.us/info_for_residents/transportation_division/round...

www.roundaboutsnow.com

JESSI PIERCE, staff writer, may be reached at 855-5859 or jessi.pierce@brainerddispatch.com. Follow her on Twitter at www.twitter.com/jessi_pierce (@jessi_pierce).