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Roundabouts

US-131/M-86 roundabout at Fife Lake in MDOT's North Region.
Department of Transportation

Roundabouts

A roundabout is a circular intersection design increasingly being used by MDOT. While some people use the term "roundabouts" and "traffic circles" interchangeably, they are not the same thing. Roundabouts are typically smaller than traffic circles, and drivers must yield to vehicles already in the roundabout before entering.

Roundabouts have been proven to safely decrease traffic delays and congestion. When selected and designed correctly, roundabouts can handle a high volume of traffic, including commercial trucks and large emergency vehicles.

Resources

Why does MDOT build roundabouts? 

Roundabout traffic laws (page 35)

Roundabout: Sharing the road

Roundabouts - A safer choice

MDOT roundabout photos

Benefits all around

Safety

Roundabouts reduce vehicle speeds, as well as the number of conflict points. Roundabouts reduce head-on/left-turn and angle-type crashes that frequently result in serious or fatal injuries.

Reduces congestion and pollution

The use of yield signs instead of stop signs or traffic signals in roundabouts minimizes vehicle stops and idle time. Less idle time means fewer emissions, reduced delays, and increased intersection capacity.

Saves money

Roundabouts reduce long-term operational and maintenance costs associated with traditional signalized intersections. There are no traffic signals to power and maintain, which can amount to cost savings each year.

Aesthetics

Roundabouts provide an area for community green space and landscape architecture. There are no large poles, overhead wires or signals to clutter the visual environment.

How to drive a roundabout Video

How to drive a roundabout

Roundabouts are easy to navigate and safer than traditional intersections. Remember, traffic in the roundabout always moves counterclockwise.

  • Choose your lane before entering.
  • Yield to traffic already in the roundabout.
  • Yield to pedestrians in crosswalks.
  • Indicate your exit by using your turn signal.
  • Use signs and pavement markings to help guide you.
Additional roundabout videos

Why does the middle of a roundabout look like that?

Many roundabouts have vegetation or landscaping in their centers. In addition to aesthetics, there are practical and safety reasons. Maintenance of those areas can pose a challenge for crews, and the safety risk and financial costs can be greatly reduced by creating areas that do not require frequent or regular maintenance.

There also are safety and operational reasons for these areas:

  • They block the glare of oncoming headlights across the roundabout.
  • The raised center gives motorists the visual cue to reduce their speed when approaching the roundabout and clearly indicates to drivers they cannot pass straight through the intersection.
  • The vegetation or barriers direct drivers’ attention to the right and left, the directions from which vehicular and pedestrian traffic matter at a roundabout.
  • The landscaping discourages pedestrian traffic through the roundabout center.
An MDOT roundabout showing the vegetation in the middle.