Montana Department of Transportation

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Montana Traveler Information

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Frequently Asked Questions

Q. Which lane should I be in to turn right/go straight/turn left?

Approach the roundabout as you would a typical four-way intersection. Be in the right-hand approach lane if you intend to turn right, be in the left-hand approach lane if you intend on making a left or U-turn, and any approach lane is OK if you are proceeding straight.

Q. If there are two vehicles side by side waiting to enter the roundabout, who has the right of way?

If there are two lanes entering but only one lane around the roundabout, both vehicles may enter the roundabout at the same time, but it is recommended that the vehicle on the right lead through the roundabout. Passing is discouraged within the roundabout.

Q. Once I'm in the roundabout, should I stop to let other vehicles enter the roundabout?

No, do not stop except to avoid a collision. You have the right-of-way over entering traffic.

Q. Which lane do I exit to?

Exit the roundabout as you would a typical four-way intersection. If you made a right-turn, use the outside (right) exit lane. If you made a left or U-turn use the inside (left) exit lane. If you went straight, use whichever lane you were in when approaching the roundabout. As you exit the roundabout, watch for vehicles to your outside that may continue to circulate around the roundabout.

Q. What determines the size of a roundabout?

Factors that determine the size of a roundabout generally include the amount of traffic, the size of the largest vehicle, and an appropriate travel speed.

Q. Are roundabouts appropriate everywhere?

No. The choice of using a roundabout versus a traffic signal is a case-by-case decision.

Q. I’m not a confident driver. Should I just drive in the outer lane?

No. You must drive in the proper lane. If you are turning left, enter from the left lane and travel in the inner lane of the roundabout. If you are turning right, enter from the right lane and travel in the outer lane of the roundabout. If you are driving straight through the roundabout, you may enter from either the left lane or the right lane. Do not change lanes within the roundabout.

Q. I drive a big truck, and that roundabout looks awfully tight. Will I fit?

Yes. The roundabout is designed so that large trucks can stay within their lane.

Q. What if an emergency vehicle comes through the roundabout?

If you have not yet entered the roundabout, let the emergency vehicle pass you. If you are in the roundabout, continue on and exit as normal, then pull to the right where there is room for the emergency vehicle to pass. Do not stop inside the roundabout because you may block the emergency vehicle.

Q. What about snow removal at roundabouts?

A number of communities in snowy areas have installed roundabouts. All have indicated that while there are some changes at first for snowplow crews, there are generally no major problems with snow removal in roundabouts. Often one truck will start on the truck apron and plow around the roundabout to the outside, while another truck will plow each entry and exit, pushing the snow to the outside. Roundabouts also make it easier to turn snowplows.

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