If you have ever hit every single red light on a stretch of road, sat at red light for what seems like an eternity when no one is coming in the other direction or taken three light cycles to get through one light, you may think there is no rhyme or reason to when lights turn green and how long they stay that way. But the truth is months of data collecting, analyzing and planning go into timing a light system and ensuring the smoothest traffic flow possible.

“There is a lot that goes into timing a light,” said Adam Lough, UDOT Region 3 traffic signal engineer. “We do a lot of traffic counts, morning, noon, night, off-peak, peak. We have systems that can collect data real time.”

In fact, engineers at UDOT and with Orem city have collected four and a half hours of traffic data a day for the last six months, measuring traffic at 71 intersections throughout Orem in preparation for rolling out a new light timing system in Utah County.

Keith Larsen, traffic operations manager for Orem, said a new timing system hasn’t been put in place since before work began on the I-15 project in January 2010. He said with all the construction and traffic impact it didn’t make sense to implement a new system. Larsen said Orem has a goal to update timing systems every two years, but Lough said UDOT makes sure lights throughout the state are updated every three years. The good news is that the amount of planning that goes into light timing means adjustments are rarely needed.

In Utah County UDOT works with individual cities on making timing plans for several time periods throughout the day, for special events and weekends. The University Parkway-State Street intersection in Orem is the nexus of traffic around which the rest of the county is built.

“We’ll start with that intersection and then roll out the timing plans for Provo, Lindon, Pleasant Grove, American Fork and Lehi,” Larsen said. “UDOT is all ready to go with those plans.”

But once a plan is in place work isn’t done for those at UDOT or the city traffic control centers. Traffic is constantly monitored for any problems and backup plans can be put in place in seconds. Lough said they have contingency plans for BYU football games, accidents on major roadways and other incidents. Larsen said the city has a plan for the Stadium of Fire, which he said is the biggest traffic event in Utah.

Larsen and his staff at the Orem traffic operation center normally watch the roadways via cameras in their office but on the night of Stadium of Fire they are in the control center ready to make changes if needed. Larsen said that since the implementation of the new statewide traffic system and timing plans, they have been able to cut the time it takes to clear traffic after the event from two hours to one.

Lough said Utah is the only state that has all of its traffic lights on the same system, which allows traffic engineers to make sure traffic flows smoothly from one city to the next.

“The residents don’t know if UDOT or a city controls certain lights; all they care about is getting from Point A to Point B. We want to make sure we have a seamless system so that people driving through still see the seamless ride,” Lough said. “We are able to do that because we are all on the same central system. We coordinate very closely with our partners. Most cities have their own mini traffic management center and they can upload timing plans whenever they need to because the system is the same.”

Lough said that it takes less than five minutes from the time a new timing plan is uploaded until it will take effect at the stop lights.

Taylor Forbush, a traffic engineer for Orem, said coordinated traffic signals aren’t used 24 hours a day. In Orem, traffic coordination begins at about 6:30 a.m. on weekdays, 8 or 9 a.m. on Saturday and after 10 a.m on Sunday. Coordination ends at 10 p.m. on weekdays and 11 p.m. on weekends and during nighttime hours traffic lights are run by sensors. Those times can vary based on how much traffic a street sees. After hours the lights on the main corridors stay green unless a car is detected on the side street.

“There is not as much demand at night and you are delaying the side streets by keeping the main corridors green for a certain period of time,” Forbush said. “During the day by coordinating we might be delaying side streets but we are saving all delays. But at night people will start running red lights if they sit at one with no one coming for too long.”

Forbush said the typical light cycle is 120 seconds, meaning the longest you would ever sit at a red light is one and half to two minutes. However, they get calls from people saying they have waited for five minutes at a light.

Even during the day left turn signals are run by sensors so time is not wasted on a green arrow if no one is turning. Larsen said they can manually override the system if necessary, but with all the data and planning that goes into traffic timing the need for that is rare. He also said emergency vehicles are equipped with sensors that traffic signals sense and turn the light green for the oncoming ambulance or fire truck. Occasionally it can take up to five minutes for the system to return to its normal timing after an emergency vehicle has disrupted the cycle.

The new stop light at 750 East and University Parkway in Orem will be included in the timing plans that will be rolling out in the next few weeks. Lough said that light will be in effect by early next week. The light has been talked about for years but is being put in place now to avoid the need for further construction in the future. With the UTA Bus Rapid Transit anticipating a stop in the area the light will provide a safe way for pedestrians to cross the street, as well as easy access to and from University Mall for drivers. Lough said because the light has been worked into plans it doesn’t mean drivers will necessarily be stopping more.

Larsen said light timing is like a science and although the changing from red to green may seem random it is anything but. He said that with light timing they have been able to reduce travel time on State Street in Orem from 17 minutes down to 12. Forbush said they expect the rollout of the new system to improve travel times as well.

“It hasn’t been updated in almost four years and traffic volumes and demands change over time,” Forbush said.

So is there a secret for hitting fewer red lights? Don’t speed. Larsen said drivers who gun it out of green lights often make it to the next light before it turns green.

“I always tell people if they want a smooth ride without much stopping don’t be at the front of the pack,” Larsen said. “If you are in the middle of pack you get to the next light after it’s turned green and traffic has a chance to starting moving.”

If you see a light that is malfunctioning or think the timing could be improved you can let UDOT know by calling (801) 830-9304 or email them at udotregion3@utah.gov.