All About Roundabouts

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A roundabout is a circular intersection where vehicles move in a counterclockwise motion around a center island. This circular intersection does not have traffic signals or stop signs. The drivers entering the roundabout yield to the vehicles already in the roundabout, then enter and exit at their desired street.

Roundabout Features

YIELD

Why are Roundabouts beneficial?

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  1. Roundabouts have fewer conflict points compared to a conventional 4-way intersection.
  2. The central island and splitter island force the vehicles to slow down. This in turn lowers the chance of serious injury or fatal crashes, improves visibility of pedestrians/bicyclists, and provides more time for drivers to react and to make way for emergency vehicles.
  3. Roundabouts do not require constant maintenance and have the ability to operate even during power outages.
  4. Roundabouts reduce time spent on waiting at the traffic light during off peak hours and is efficient in keeping vehicles moving.
  5. It makes the street safe for pedestrians and bicyclists to cross as the splitter island also plays the role of a refuge island (i.e. a small section where pedestrians and bicyclists can wait before finishing crossing a road).

A Roundabout is NOT a Rotary!

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Roundabout
Rotary
Size Generally smaller in diameter Typically larger in diameter and has a wider cirulating roadway
Speed Designed to lower speeds (25 mph or lower) May allow higher speeds (40 mph or higher)
Operation Vehicles on the circulating road have higher priority Priority of vehicles can vary
Traffic Control Uses yield sign at entry May use traffic signals
Lane changing Lane changes are not encouraged due to design May allow lane changes
Pedestrian Access Pedestrian crossings are usually away from entry or exit. Pedestrian facilities may vary
Bicycle Access Bicyclists usually share their path with other vehicles or separate lanes may be provided May not accommodate bicyclists
Safety Tends to have less severe collisions Collision rates and their severity can be high

Navigating Roundabouts

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Rule #1:

Slow down! Going slower provides ample amount of time to make decisions and better prepare to yield for other road users (other vehicles, pedestrians, bicyclists). 

Rule #2:

Look Around!  Drivers should decide on which lane to exit after entering the roundabout. It is important to check the crosswalks to see if anyone is waiting to cross or is already in the process and should be ready to stop and let them safely cross.

Rule #3:

Be ready to yield! If there are large vehicles like trucks or buses are in the roundabout, drivers should give them space and avoid driving next to them. While exiting the roundabout, it is important to look around for other road users and prepare to yield. 

Emergency Response

Screenshot_19-11-2024_122553_www.mass.govSource: Guidelines for the Planning and Design of Roundabouts (mass.gov)

  • Always yield to emergency vehicles
  • If you have not entered the circulatory roadway, pull over and allow the emergency vehicles to pass.
  • If you have entered the circulatory roadway, continue to your exit, then pull over and let the emergency vehicles pass.
  • Avoid stopping in the roundabout.

Roundabouts in Lowell

Screenshot_19-11-2024_12393_cityoflowellmass.sharepoint.com