“What’s up with that traffic signal?”
Have you ever asked that question while sitting at a red light? Traffic signals are frequent targets of verbal abuse, especially when they are on the blink (pun intended!). And you always seem to catch that red light when you’re late for an important appointment.
How hard can it be to make these things work right, anyway?
Keeping our traffic lights maintained and operating efficiently is a bigger job than you might think. The City of College Station’s Traffic Division maintains and operates 70 traffic signals, 50 pedestrian/school zone flashers, more than 12,000 traffic signs and over 100 miles of long-line pavement markings.
Retiming Improves Traffic Flow
Most drivers are not concerned about progression, synchronization and coordination – they just want to get where they’re going without stopping. We’d all like to drive the length of Texas Avenue without any stops, but that would only create excessive delays on major side streets such as Harvey Mitchell Parkway, Southwest Parkway, Holleman Drive, Harvey Road, George Bush and University Drive. Every second of green we give drivers on Texas Avenue would add a second of red to those on intersecting streets.
Still, we keep a close eye on traffic patterns and frequently retime the signals along our major arteries. This has proven to be a cost effective way to significantly reduce wait time and help traffic move more smoothly. A recent synchronization on one roadway reduced travel time by 40 percent during the evening rush hour and by 24 percent during the peak morning time.
However, retiming the signals along major roadways such as Texas Avenue is not a simple task. Factors we must consider include pedestrians crossing the street, cars entering and exiting businesses, preemption by emergency vehicles, construction projects and the amount of traffic on intersecting streets, which average more than 20,000 vehicles a day. Those and other variables prevent perfect coordination from being a realistic goal, although we strive to make it work as well as possible.
Trains, Football Games and Emergencies
To reduce delays to emergency responders such as the fire department, our traffic signals use a preemption system to allow fire engines and ambulances the right-of-way. With as many as 20 trains passing through each day, the railroad tracks in the Wellborn Road corridor also present challenges since trains preempt the signal’s normal operation. Once a signal is pre-empted, it can take four or five cycles for it to synchronize again, depending on the amount of traffic on the side streets. The lower the traffic volume, the faster the signals are coordinated.
For major events such as Texas A&M football games, we use special signal programs to ease congestion and keep traffic moving. The system is set up from the mainframe computer and downloaded to each signal for inbound and outbound traffic flow. Without reliable communications media, the signals would not be able operate efficiently for special events or daily operations. We use fiber optics to communicate with some signals using wireless radios, and we plan to add more signal groups to our fiber network.
Inspections Prevent Problems
College Station’s traffic signals are thoroughly inspected each month to make sure that vehicle detection, signal indications and pedestrian pushbuttons are operating properly. Signal cabinets are cleaned regularly, and exhaust fans are checked along with the date, time and coordination program. With summer temperatures inside the housing reaching as high as 140 degrees, it’s crucial for the exhaust fans to be working. We repair most problems on the spot through our monthly preventative maintenance program, which keeps after-hour calls to a minimum and maintains the high level of safety you expect.
Technology Saves Money
Our biggest cost savers are the Light Emitting Diodes (LEDs) used in all but four of the city’s traffic signals. Typically, the LEDs trim power usage by about 75 percent per signal. In pedestrian signals, we use LEDs with countdown timers as an additional safety component. All of our new signals – and about 25 percent of our overall system – use Uninterruptible Power Supply (UPS) units, which keep the signals working for six hours or more during a power outage.
Primary Goals: Safety and Efficiency
As one of six divisions in the City of College Station’s Public Works Department, the Traffic Division strives to provide you with a safe and efficient transportation system while improving mobility through new technologies and well-trained technicians. Our foremost goals are to not only be responsible stewards of our financial resources, but to save you time, reduce fuel consumption and emissions, and above all else, to keep your transportation system safe.
Troy Rother
City Traffic Engineer | Traffic Division, Public Works Department
Lee Robinson
Traffic Systems Superintendent | Traffic Division, Public Works Department
Garrett Martinek
