The Arizona Republic
Arizona drivers can expect to face a new challenge: the European
roundabout, which state transportation officials have approved
as an alternative to traffic signals at 15 major interchanges.
In the traffic land of straight lines and signalized grid
systems, they are signal-less circles where motorists merge
and putter around without stopping.
Lou Murphy, 74, who lives in Mesa during the winter, was
skeptical. She said a roundabout in her home city of Clearwater,
Fla., confused and angered motorists.
"People down here (in Florida) drive like they do in
Arizona, fast and furious, and you can't do that in a roundabout,"
But roundabouts are becoming the rule. Under a new state
mandate, engineers and designers have been ordered to consider
roundabouts, a cheaper alternative to normal interchanges,
as an option for future projects.
There's no question public education will be needed, said
Matt Burdick, an Arizona Department of Transportation spokesman.
The next edition of state driver's manuals will contain a
section on using roundabouts.
"It's completely different as far as the driving culture,"
Burdick said. "We are used to driving straight and driving
fast in our intersections."
Up to 31 roundabouts are being considered for traffic interchanges
from Flagstaff to the Mexican border. Designs already are
under way for six of the sites, Burdick said.
That includes the Interstate 17 interchange at Cordes Junction
for Prescott-bound traffic.
Roundabouts have been proposed for Brown and McKellips roads
along a planned future leg of Loop 202. Residents in northeast
Mesa have been generally supportive of the idea.
The plans will go to the City Council on May 6. If approved,
the roundabouts will be built in three years.
A citizen advisory board approved the plans unanimously Tuesday,
but not without some debate.
Board member Chester Wilt expressed his apprehension, saying
that sometimes even a straight road confuses him.
Extensive public education is needed, and there's little margin
for engineering error, said Gene Russell, a retired Kansas
State University professor specializing in roundabout-operations
"It's more an art than a science," he said. "They
(designers) think, 'I'll take it out of the federal manual,'
but it's easy to screw them up."
For details, see the state's only major public roundabout,
at Interstate 17 and Happy Valley Road, said Steve Wilcox,
an ADOT designer. The state is planning to alter it so cars
can enter side by side at a steeper angle because there are
too many fender-benders in the circle. Construction is planned
for next year.
State officials are working with Barry Crown, an Englishman
who is the world's premier roundabout consultant.
Russell cautioned that roundabouts should be taken on a case-by-case
"Even I wouldn't say 'Put them everywhere,' " he
said. "But it should be part of the process and in the
toolbox of any traffic engineer."
Officials say roundabouts are an efficient cost-effective
way to move large amounts of traffic safely through major
They're cheaper than other intersections, which can require
bridges, traffic signals and electricity to run the signals.
Signals for one Mesa intersection cost about $100,000, in
addition to an annual electricity cost of $1,560, said Dan
Cleavenger, an assistant Mesa traffic engineer.
"They've converted me," he said. "I didn't
have experience with roundabouts very much, but with graphics
and simulations they've used, I'm absolutely willing to try
Officials cite a 2000 study from the Insurance Institute
of Highway Safety, which looked at crashes and injury statistics
at 24 intersections before and after roundabouts.
The study said roundabouts reduce overall crashes by 39 percent
and injury-producing crashes by 76 percent. Fatal collisions
dropped 90 percent, according to the study, largely because
of low speeds.
Mesa's proposed roundabouts would have pedestrian crossings,
clearly marked lanes and signs. Speeds would be kept under
25 mph; there would be no left-turn lanes.
Traffic coming into the roundabout would yield to the traffic
already within it, a key difference between roundabouts and
their ancestor, the ill-famed traffic circles or "rotaries"
found back East.