Roundabouts Frequently Asked Questions

Not really. The main similarity is that both roundabouts and four-way stop intersections do not have signals. The differences include: four-way stops yield to whoever arrives first, or the vehicle on the right, roundabouts yield to the left---like a right turn on red---because the circulating traffic comes from that direction. At four-way stops, each direction gets a turn in order. At roundabouts, each driver chooses a safe gap to enter and no driver "gets a turn."

The center island is the circular central island around which traffic circulates; this island may be raised or flush with the roadway surface; a mountable/drivable truck apron may surround the center island; the truck apron accommodates the path of the rear left wheels of larger vehicles such as semi-tractor trailers, farm equipment, buses, etc.; the truck apron is generally constructed with a different material to discourage passenger vehicles from driving over it.

The circulatory roadway or circulating lanes is the roadway around the central island on which circulating vehicles travel in a counterclockwise direction, entering and exiting only to the right.

The spitter island is a raised or painted island separating entering and exiting traffic and placed within a leg of a roundabout; the splitter island also serves to deflect and slow entering traffic, as well as provides a refuge/safety zone for crossing pedestrians.

The yield line is a broken line marked across the entry roadway where it meets the outer edge of the circulatory roadway and where vehicles wait, if necessary, for an acceptable gap to enter the circulating flow; if no traffic is in the roundabout, entering traffic may proceed without stopping.

At roundabouts, the traffic circulates counter-clockwise and moves toward vehicles at the yield line. Vehicle operators should always yield at the entry to circulating traffic. In practice, that means yield to traffic from the left, similar to the action that is necessary when entering a freeway or turning right at a red traffic light/signal.

Yes. Especially when exiting the roundabout. This allows vehicles waiting to enter the roundabout to know your intentions.

Roundabouts are not like four-way stops in the fact that there is not taking of turns among vehicle operators. Vehicle operators should enter the roundabout when there is a safe gap in the traffic flow.

It depends on the amount of traffic already in the roundabout. When there is a lot of traffic, vehicle operators will probably have to stop at the yield sign and wait for a safe gap before proceeding. If a safe gap already exists, operators are not required to stop. However, vehicle operators should always slow down enough so they can stop, if necessary.

This is a good-judgment decision based on the vehicle being driven, weather conditions, and traffic flow. It is always the vehicle operator's responsibility to select a safe gap before crossing the yield line.

Vehicle operators in the roundabout may slow down so that the safe gap becomes more obvious to the driver wanting to enter the roundabout; however, they should not stop. Vehicle operators should not stop after crossing the yield line and are actually in the roundabout circle.

The only priority rule is that drivers inside the roundabout have the right-of-way over any driver entering the roundabout, regardless of approach direction. Every entrance has a yield sign for approach vehicles.

Be patient and wait for them to choose their safe gap. Try to avoid horn honking because it tends to cause less confident drivers to make mistakes.

Vehicle operators should remain behind the pedestrian crosswalks until there is room for their entire vehicles to travel beyond the crosswalk.

First, practice defensive driving. Second, all drivers should try to set the right example by obeying the traffic signs, and others will learn and follow suit. All drivers should drive at a safe and consistent speed so other drivers can easily judge the traffic flow speed.

Drivers should be aware that routine landscape maintenance is common at roundabouts. Be courteous and drive cautiously when maintenance personnel are present.

Vehicle operators should not change lanes once crossing the yield line and are in the circle portion of the roundabout. If there is a need to change lanes, vehicle operators should do so before reaching the yield line. A roundabout is like any other intersection. Get in the left lane to turn left and right lane to turn right.

No.

Most multi-lane roundabouts are designed, signed and striped to minimize this problem by leading traffic to the exit points. If all else fails, simply go around once and try again.

Multi-lane roundabouts should be approached the same way as any other intersection. To turn left, use the left-most lane and signal for a left turn. To turn right, use the right-most lane and signal for a right turn. In all situations, vehicle operators should pass counterclockwise around the central island. When preparing to exit, vehicle operators should turn on their right turn signals as soon as they pass the exit before the one that will be used.

If the roadway in the roundabout is wide enough, vehicle operators should pull as far to the right as possible and allow the emergency vehicle to pass. However, it is generally better to completely clear the intersection and pull off to the side past the roundabout.

Vehicle operators should remember to observe all the pedestrian crossing locations because pedestrians always have the right-of-way when they are in the crosswalks. Vehicle operators should never stop in the crosswalk while waiting for their turn at the yield line.

Pedestrians should always use the crosswalks; and make sure the vehicle operators see him/her before entering the crosswalk.

Bicyclists have a legal right to ride on most roadways just like motorized traffic. Roundabouts are just like other intersections in that bicyclists may either follow the rules of the road and maintain travel on the roadway or use available paths and crosswalks to safely bypass the roundabout.

Very large trucks can pass through roundabouts and will need both lanes to make wide turns. They can use the truck aprons (concrete area on the outside of the central islands) for additional space. Other drivers need to give trucks plenty of room. Expect trucks to use both lanes and don't get beside a truck in a roundabout because they may not be able to see smaller vehicles

Yes. The roundabout has been designed specifically to accommodate large tractor-trailer units. As truck operators approach the roundabout, they should stay close to the left side of the entry. When passing through the roundabout, the trailer may track over the special apron around the central island - it was designed specifically for this purpose. When exiting, stay close to the left side of the exit.

At a multi-lane roundabout, tractor-trailer units may need to occupy the entire circulatory roadway to make the turn. Truck operators should signal their intention to do so in advance and claim both lanes on approach to the roundabout.

A number of communities in Iowa and other snowbelt states have installed roundabouts. All have indicated that while there is some initial adjustment in procedures for snowplow crews, roundabouts generally present no major problems for snow removal.