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
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