Photos

Roundabouts

What you need to know about
Modern Roundabouts


Roundabout Diagram

Each year the City of Lawrence receives numerous requests from citizens to improve the safety of the streets on which they live. In an effort to find appropriate ways to deal with these concerns and make our residential areas more livable, the City has started considering the use of roundabouts.

Modern roundabouts are relatively new to the United States, but they have been used throughout Europe, Australia and other countries to reduce crashes, injuries, traffic delays, fuel consumption, air pollution and construction costs, while increasing capacity and enhancing intersection beauty. They have also successfully been used to control traffic speeds in residential neighborhoods and are accepted as the safest type of intersection design.

A modern roundabout is a circular intersection similar to the traffic circle used previously in this country. The major differences between a traffic circle and a roundabout are:

  • Yield at Entry: At roundabouts the entering traffic yields the right-of way to the circulating traffic. This yield-at-entry rule keeps traffic from locking-up and allows free flow movement.
  • Deflection: The entry and center island of a roundabout deflects entering traffic to slow traffic and reinforce the yielding process.

Types of Roundabouts

There are two basic types of modern roundabouts:

Conventional roundabout diagram
Conventional roundabout
A one-way circular roadway around a curbed central island for circulating traffic, usually with flared approaches. This type is constructed at the intersection of Harvard Road & Monterey Way.
Mini-roundabout diagram
Mini-roundabout
A one-way circular roadway around a raised central island of up to 30 feet in diameter, usually without flared entries. This type is constructed at the intersection of 18th Street & Sweetwater Court.

Why Use A Roundabout?

There are only four potential conflict points in a roundabout.

Conflict points at a roundabout.

There are many more potential conflict points in a standard four-way intersection.

Conflict points at a standard intersection.