SPECIAL AIRHEADZONA EDITION!!
According to the Arizona Department of Transportation
("ADOT"), a roundabout is a one-way circular intersection without
traffic signal equipment in which traffic flows around a center island.
The
modern roundabout functions with yield control at the entry points, and gives
priority to vehicles within the roundabout.
Roundabouts keep traffic moving through an intersection, so
the potential for crashes in the center are diminished. Drivers move at a
slower speed, usually 25 mph.
According to ADOT, modern roundabouts reduce
accidents by 40% to 60%, reduce injury accidents by 80% and fatal accidents by
as much as 90%. In addition, eliminating a traffic signal saves the city money
on installations, maintenance, and electricity.
I live near the first two roundabouts placed in service in Phoenix. They started with a disadvantage because you have a four-lane street going into a one-lane circle at a major highway intersection, with a one-lane bridge crossing the highway.
The right answer would have been to make the bridge and the circles two lanes, and I am sure that was not done due to cost.
There are social networking pages related to these circles, if you want to read what the residents think.
I live near the first two roundabouts placed in service in Phoenix. They started with a disadvantage because you have a four-lane street going into a one-lane circle at a major highway intersection, with a one-lane bridge crossing the highway.
The right answer would have been to make the bridge and the circles two lanes, and I am sure that was not done due to cost.
There are social networking pages related to these circles, if you want to read what the residents think.
The success of a roundabout is based on two assumptions that AZDOT has made.
(1) That traffic keeps moving. It doesn't. At the roundabouts near my home that involve the highway exits and the frontage roads, there is always some idiot in the roundabout (they have the right of way at this point) who will STOP because he sees a car on the main street. Of course, the car on the street also stops and they look at each other for a few moments while traffic backs up.
(2) That drivers move at a slower speed. They don't. even though these roundabouts are posted at 25 mph, drivers in Arizona, while not very bright, have lead feet, so after stopping unnecessarily, they'll take off a fifty, only to slam on their brakes ten feet later for the next idiot who can't navigate the circle.
I have an idea-let's take all the people who cannot navigate a traffic circle and put their heads under a running lawn mower!