What is a Roundabout?

Simply stated, a roundabout is a transportation management tool that moves traffic through an intersection without the aid of traffic signals. More specifically, a roundabout is an intersection with one-way circulation around a central island where entering traffic must yield the right-of-way to the traffic circulating within the roundabout. A roundabout should not be confused with traffic rotaries or circles, which are much larger, with higher speeds and multiple lanes for entering and exiting. As traffic volumes increase, collisions and traffic jams can occur because vehicles are not required to yield to traffic before entering.Traffic engineers recognized the deficiencies associated with traffic rotaries and circles, and incorporated slower speeds and "yield on entry" into roundabouts.

Why is the city building roundabouts?
Engineering analysis has determined that roundabouts can perform more effectively than traditional signals at many intersections. For instance, studies indicated that signalized intersections cause unacceptable traffic delays and congestion.Although roundabouts are not appropriate for all intersections, they do provide our community with another tool to address traffic congestion and to further enhance the safety of our roadways.

Roundabout benefits...
There are a number of benefits associated with this type of intersection control:

Safety A key benefit of modern roundabouts is safety. According to the Federal Highway Administration, installing a roundabout typically results in:   A 76% reduction in injury-accidents A 90% reduction in fatalities A 40% reduction in pedestrian injuries, and 75% few conflict points compared to standard intersections (see chart below)

	Less Delay Roundabouts are designed to handle traffic more efficiently than signalized intersections. With traffic constantly moving and vehicles entering the intersection at lower speeds, more vehicles are able to move through the intersection at any given time.
	An Improved Environment Since roundabouts reduce the amount of time vehicles spend idling at intersections, they provide environmental benefits by reducing fuel consumption and exhaust emissions.

	Slow Down: Driving speeds in roundabouts are 15 m.p.h. or less.
	Lane Choice: Drivers must make the appropriate lane choice, based on their destination, prior to entering a multi-lane roundabout. As in a standard intersection, use the left lane to make left-turns, U-turns, or straight-ahead movements; use the right-lane to make right-turns or straight-ahead movements (see charts below). Never pass or overtake another vehicle after entering a roundabout.
	Yield Principle: When preparing to enter a roundabout, yield to all traffic in all lanes already circulating within the roundabout.
	Large Vehicles: Give special consideration to trucks, trailers, and other large vehicles. Never pass or drive adjacent to large vehicles within a roundabout.
	Emergency Vehicles: Do not impede emergency vehicles. If you are within a roundabout when an emergency vehicle approaches, move through, exit, and then pull over.
	Pedestrians: All pedestrians must cross at the designated crosswalks. Although vehicles are required to stop for pedestrians, always exercise caution when crossing.
	Bicyclists: Bicyclists are encouraged to walk their bikes and use the pedestrian crosswalks. Only experienced bicyclists should ride within the roundabout. Where available, bicyclists are to use the 10 foot wide sidewalks.

Standard Intersection	Multi-lane Roundabout
Single-lane Roundabout

	Contact City Staff You can contact City of Tumwater staff at:   City of Tumwater Jay Eaton, Public Works Director   Phone: 360-754-4140