intersections with signals or stop signs. This is especially true of
crashes resulting in occupant injuries.
Researchers found a 39% overall decrease in crashes and a 76%
decrease in injury crashes. Collisions involving fatal or
incapacitating injuries fell as much as 90%. These findings are
consistent with those from other countries where similar
traffic-calming measures have been used extensively for decades.
These safety benefits do not come at the expense of traffic flow.
In fact, when traffic circles replace intersections with stop signs
or traffic signals, delays in traffic can be reduced by as much as
Another feature is that all cars are able to move continuously
through intersections at the same safe speed.
People assume that because there are so many traffic signals and
stop signs out there, they must be efficient. The fact is, they're
not. When cars are stopped at an intersection, delays are inevitable.
It may seem counterintuitive that traffic circles increase capacity
while lowering speeds, but that's exactly what happens.
The universal habit for fast driving has created a culture,
especially in Glendale, where "slowing down" is seen as an
encroachment on convenience.
But this bias for speed isn't just among drivers. Until recently,
the priority for road planners and engineers has been to process as
much traffic as possible. Fortunately, concerned citizens and traffic
engineers in Glendale have the insight to learn from countries in
Europe and elsewhere, where progressive thinking has focused on
traffic calming, making the streets safe for all.
A normal right-angle intersection will place vehicles on a
collision course, with crashes avoided only if drivers obey traffic
laws and use good judgment. Research shows many drivers don't. So the
potential is high for right-angle, left-turn, and rear-end conflicts.
These accidents make up about two-thirds of police-reported crashes.
The very geometry of traffic circles eliminates many of the angles
and traffic flows that create crash opportunities, particularly the