Roundabout

While not an interchange design, roundabouts can be used at intersections located near an interchange to help increase safety and keep traffic moving.

A roundabout is a way to get large volumes of traffic through an intersection quicker, safer and more economically. Used in many foreign countries, the one-way circular intersection channels traffic around a central island without the use of traffic signals. Drivers slow down as they approach the roundabout and yield to the traffic already circulating. Drivers then enter to the right when a gap opens, keeping the free-flowing movement going. By yielding instead of stopping at a signal, motorists can be on their way quicker.

Roundabouts add to driving safety by reducing a signalized intersection’s 22 conflict points (spots where vehicles could collide) to eight. The fewer conflict points, combined with slower speeds and calmer traffic, can translate into fewer – and less severe – crashes. Roundabouts help lower costs by reducing driver delay, which saves time and fuel, and reduces pollution. The state also benefits by eliminating about $5,000 per year in maintenance of signals and electricity costs.