The City of Carrollton currently maintains 106 signals. Each of these traffic signals was installed in accordance with the Texas Manual of Uniform Traffic Control Devices (TMUTCD).
The TMUTCD states that traffic control signals should not be installed unless it is justified by “an engineering study of traffic conditions, pedestrian characteristics, and physical characteristics of the location.” The study must indicate that this installation “will improve the overall safety and/or operation of the intersection” and it must consider whether or not it “will reduce the amount of road user delay at the intersection.” Overall, the “traffic control signal should not be installed if it will seriously disrupt progressive traffic flow” (pg 445; 2006 ed).
If you have further questions or would like to report a problem, please call 972-466-3425.
Mounted Metal Wind Wings
These flat metal objects that can be observed above the signal head, have been given the name "wind wings." The purpose of the wind wing, is to eliminate signal arm bounce whenever there is a wind of approximately 15 mph or greater. This is a standard practice used on all signal arms over 25 feet in length, since 1978.
"Sparkling" Red Lights
These lights are called LEDs (Light Emitting Diodes). Red LED signals use very little energy, just 10.5 watts. The standard signal lamp uses 135 watts and has to be replaced annually. LEDs are semiconductors that emit electromagnetic energy, coincident with the change of energy state, at a diode junction. Simply put, LEDs are miniature lights that use up to 90% less energy than a comparable incandescent light. The lamp-life is extended beyond 10 years, compared to 1 to 2 years for an incandescent lamp. The use of LED traffic lamps, results in significant reduction in energy, environmental issues and signal maintenance. The use of LED technology reduces the overall utility bill by reducing the energy consumed and the electrical demand load. It also helps protect the environment since there are fewer harmful emissions associated with use (that is, less fossil fuel is required to produce electricity). With an average life of 10-15 years, yearly bulb replacement and maintenance are eliminated. The City of Carrollton standards call for the use of Red, Green and Pedestrian LEDs on all new or rebuilt traffic signals.
Black Camera-Like Devices
The black canister mounted on top of the signal arm is for fire preemption, and is called an Opticom system detector. The Opticom system uses high energy infrared technology to grant authorized emergency vehicles momentary right-of-way at signalized intersections. The Opticom system gives an authorized Fire Department vehicle advantage over other traffic, intersection by intersection, as needed. As the vehicle approaches, it saturates the intersection with an encoded, infrared signal that is received, decoded and validated to give the requesting vehicle the safest possible driving condition—a green light. Opticom has helped to provide a faster response for fire equipment to arrive on the scene.
Overhead Street Name Signs
The overhead street name sign features the City of Carrollton logo and a block number. The sheeting is white and green and is retroreflective. We use a sheeting called 3M Diamond Grade VIP (Visual Impact Performance). Unlike other reflective sheeting we use, VIP features an advanced prismatic design. As a result, it provides greater than normal reflectivity and remains highly visible to drivers in low light conditions. The prismatic cubes on VIP sheeting are specially shaped to return the light from a vehicle's headlights back to the motorist's eyes. This controlled light-return makes the sign visible longer, giving motorists more time to respond.
White Light (Red Light Confirmation Light)
White lights are used by the Police Department to assist in the prevention of red light running. Each pole has a white light mounted on it and is wired to the red light indication for that pole. The Police Officers can park downstream or anywhere visible to the white light and detect red light runners without parking at the intersection. The City of Carrollton standards call for the use of these “white lights” on all new or rebuilt traffic signals.
Decorative Pole Tops & Bases
Decorative pole tops and bases are part of the City's corridor design plan. It is difficult to make a traffic signal aesthetically pleasing to the eye, but the decorative tops and bases have helped to not only make traffic signals a little more attractive, but also help to identify ownership of our traffic signals.
This Yagi antenna is part of the communication link between the traffic signal controller and the Advanced Traffic Management Center (ATMC). With the use of spread spectrum radios, the City can proudly boast having the first wireless traffic signal system in the world. The City ATMC is staffed from 7:30 a.m. to 4 p.m., Monday through Friday. At the ATMC, city staff can monitor all the traffic signals in Carrollton. The City has the capability of uploading or downloading data to any traffic signal. There are also 8 video cameras located around the City, linked to the ATMC by microwave antennas. All solar-powered school flashers are also controlled at the ATMC.
Pedestrian signals are installed to assist pedestrians in safely crossing signalized intersections. The "Man Symbol" light gets you started crossing the intersection and the flashing "Hand Symbol" gives you time to clear the crossing. The way it works is, the "Man Symbol is on long enough to get you started into the intersection and the flashing "Hand Symbol" will get you through the intersection. If the flashing "Hand Symbol" signal is flashing before you step off the curb, you should wait for a "Man Symbol" signal before crossing. The City of Carrollton standards call for the use of LED Pedestrian Signals on all new or rebuilt traffic signals.
Pedestrian Push Button
Pedestrian push buttons are used to activate the pedestrian signals. You only have to push the button one time to receive a walk light. It will not make any difference if you hold the button in or push it many times. The controller can only see the first time you push the button. All of our pedestrian push buttons are in compliance with ADA (Americans Disability Act) standards.
Mast Arm Camera
In 2002, the City of Carrollton began using video detection cameras for vehicle detection at traffic signals. These are the camera devices that are seen on top of a traffic signal mast arm. By using video detection, the City is able to set up an entire traffic signal with vehicle detection in 4 hours versus 2 days with loop detectors. The cameras also allow the City to make changes to the detection without having to close traffic lanes or re-cut the roadway; thus, eliminating any traffic interruption. The City of Carrollton standards call for the use of video detection on all new or rebuilt traffic signals. We also have a program in place to upgrade 3 to 4 traffic signals each fiscal year with video detection.
We receive questions from citizens from time to time, inquiring about the black squares they see on the roadway. Those black squares are a road tape that is used to hold traffic counters in place. Traffic counters are used to determine whether or not a speed limit sign, stop sign or traffic signal is warranted by the TMUTCD. If a citizen requests one of these control devices, the Engineering Department will request traffic counts be performed at that location. The counters log data such as vehicle volume, vehicle size and vehicle speed. With this information, the Engineers can determine which control device, if any, is needed at that particular location. The road tape uses an adhesive that prevents it from being removed without the use of a roadway grinder. The center of the tape is cut out to remove the actual counter device, but the outside portion of the tape is left on the roadway and will eventually come up over a period of time.
There are 8 video cameras located throughout the City. Seven of the 8 cameras are linked to the ATMC via microwave antennas. At the ATMC a system operator monitors the real time video pictures. The system operator uses this information to assist in incident management. It is very helpful when calling in traffic signal problems to identify the location, the type of problem, the direction of the problem and the time of day the problem is occurring.
Solar powered, radio controlled school flashers have been a standard of the City of Carrollton since 1990. The first solar flashers were installed on Peters Colony on August 1, 1990. City staff designed and installed the first 12" double beacon solar powered school flashers in the nation and set a national standard for solar school flashers. From the ATMC we can turn on or off any or all the school flasher at any time of the day.
The Advanced Traffic Management Center (ATMC) is located in the South Service Center at 1420 Hutton Drive. It is staffed from 6:30 a.m. to 3 p.m. Monday through Friday.