Intelligent Transportation Systems (ITS)
Nearly all of
Mesa's signals are interconnected and operate as a system to
reduce overall delays throughout the City. Mesa's skilled field
technicians and staff in the City's state-of-the-art
Transportation Management Center (TMC) work together to keep
traffic moving.
Vehicle Progression
Vehicles starting out straight (e.g. not making a turn from a
side street) at a major intersection at the beginning of a green
will experience less stops and delays. The signal timing is
adjusted at various times of the day to accommodate the changing
traffic patterns. However, there are times when the amount of
traffic exceeds the capacity of the roadway. When this happens,
backups and delays are inevitable. Carefully planned signal
timing helps use the available street capacity to its utmost.
Fire Preemption
Approximately 80 percent of Mesa's traffic signals are
equipped with preemption. Fire department vehicles have special
coded transmitters that trigger the system. This equipment makes
the traffic signal give the green indication to the approaching
fire vehicle to help emergency services personnel arrive quickly
and safely to where they're needed. You may have noticed the
detectors for the system. In Mesa they are typically mounted to
the top of the signal head, at the end of the mast arm, over the
roadway.
Detecting Cars
The most common method uses a coil of wire embedded in the
road surface. An electronic signal running through the wire of
this inductive loop is affected by the presence of vehicles. An
interface.ce in the traffic signal cabinet tells the traffic
signal controller when a vehicle is present based on these
inductance changes. The principle is essentially the same as how
a metal detector used to find coins on the beach works. If the
loop of wire in the street becomes damaged, the traffic signal
controller will interpret this as if there were always a car
present. This means, for example, that a left turn arrow or
side-street indication would be displayed for its maximum time
with no vehicles present. Many recently constructed or renovated
intersections have video detection.ces which monitor the
lane usage through video input. Detection zones are drawn on an
image of the roadway. A computer program running inside the
detection.ce determines when vehicles enter a zone and pass
that information on to the traffic signal controller. There are
several advantages to video-based detection such as not being
damaged by road work, being re-programmable for situations such
as construction where lanes may be moved, and the ability to
send images back to the TMC where City staff can see traffic
incidents or congestion and make timing adjustments.
Pedestrians
Pedestrian indications consist of a walking person symbol
(i.e. "walk" indication) and an upraised hand (i.e. "don't walk"
indication). The walking person symbol means you can begin
crossing now. This indication is typically on for a short
amount of time just to get you started. The flashing hand means
if you've started crossing, finish crossing. The flashing hand
also is a warning that if you haven't started crossing yet,
don't start because it is too late to safely cross before the
signal changes. If the hand (i.e. "don't walk" indication) is
on solid you shouldn't be in the street. When crossing the
street, if there is a button present for the direction you are
traveling, please press it. When the button is pressed the
controller knows to bring up the pedestrian indications to allow
enough time for you to cross. Without the button press, the
traffic signal may only give enough time for vehicles. Pressing
the button doesn't make the signal turn green any faster but it
does give more time for pedestrians to cross the street. If
there isn't a button, don't worry, the signal will display the
pedestrian indications automatically.
Transportation Management Center
The City of Mesa's Transportation Management Center (TMC) is
bringing it all together. This facility is the nerve center of
Mesa's Intelligent Transportation Systems (ITS) efforts. This
facility houses systems which can notify City staff of any
unusual incidents. Based on this information, traffic signals
near the scene can be adjusted to better accommodate the change
in conditions. Several key intersections are monitored from the
TMC, and City staff is working diligently to expand this
technology throughout Mesa. The coordination of these efforts
all results in less traffic congestion and delays. This advanced
technology also allows TMC staff to work with neighboring cities
on monitoring traffic conditions and accidents, making your
commute an easier one. The TMC is truly one of the most advanced
facilities of its kind in the nation, and the City is pleased to
put this state-of-the-art technology to use for the benefit of
all who travel in Mesa.
New Technologies
Mesa has switched to LED (light emitting diode) traffic
signal indications instead of incandescent lamps. LEDs use a
fraction of the energy when compared to the older technology and
they have a life-expectancy of eight to ten years compared to
one to two. Several years ago Mesa started building all new
intersections with LED indications and then shortly thereafter a
retrofit program began. The switch to this more efficient
technology means that, even with an increase in the number of
traffic signals, the electric bill has dropped by over $260,000
per year!
Transportation
300 E. 6th St.
Mesa, AZ 85201
Mailing Address:
City of Mesa
PO Box 1466
Mesa, AZ 85211
Office Hours:
Monday - Thursday
7:00 a.m. - 6:00 p.m.
Closed Fridays & Holidays
480.644.2160
480.644.2262 (after hours)
E-mail
MyMesa