Troublesome intersections: State, city workers explain the nuances of traffic signals

You slam the steering wheel, curse the timid driver in front of you and turn up the music full blast to drown out the rage. You're seeing red, both literally and figuratively.

But the traffic signal is not interested in your anger. It's calibrated to keep traffic moving throughout the city, and that means it can't keep everyone happy all the time.

Each signal is fitted with an internal computer that tells it when to change colors based on overall traffic patterns, activity of surrounding lights, and whether or not a vehicle has tripped its detector.

Currently 15 traffic signal locations -- with an additional four under construction -- are operated by the Department of Public Works in Cape Girardeau. About 20 more on Route K, Kingshighway and Highway 74 are operated by the Missouri Department of Transportation.

Signals are supposed to keep vehicles moving, but drivers aren't always so sure they're working to that end. When the Southeast Missourian asked, drivers had three primary complaints about signals in Cape Girardeau:

1. The traffic lights aren't coordinated.

"The closer you get to Wal-Mart headed west on Kingshighway, the more signals there are and the closer they are together," wrote Ryan Harris of St. Louis and originally from Cape Girardeau. "You come to a stop at St. Francis Drive, it turns green; problem is that you're likely going to see a red light ahead of you at Mount Auburn and so on. Because of that, I think most motorists just kind of coast to the next intersection at an idle to moderate speed as they are only going to come to a stop again. Less traffic gets through as a result."

2. They wait too long at a light when nobody is driving on the cross street.

"Sometimes I'll get to the light at Independence and West End Boulevard at night and there is nobody around, but the light still stays red for like a minute and a half," said Andrea Hao of Cape Girardeau.

3. There is not enough time for more than a couple drivers to make turns.

"For me it's gotta be William Street in front of Cracker Barrel where you make a left turn. I've waited for 15 to 20 minutes before getting through. It'll be red for awhile, let a couple cars through and then back to red. I don't even think there are sensors there," said Les Respondek of Cape Girardeau.

Officials in charge of transportation offered a number of responses. Steve Hoernig is the MoDOT operations engineer based in Sikeston. Kelly Green is the traffic operations engineer for the city of Cape Girardeau. She is the first person to hold this position and formerly worked for MoDOT. The two oversee state and local signals respectively.

Hoernig said he's working on coordinating the lights.

"We're going to revise the timing for the whole corridor from Cape Rock Drive to Southern Expressway along Kingshighway," said Hoernig. "People have complained that they have to stop at every signal. If you get a signal at the beginning sometimes you get balled up in the middle. We'd like to make it where if you're going south you can at least get to Route K."

Hoernig blamed some of the problems on electrical malfunctions caused by lightning strikes.

"It can fry the wiring," he aid. He also said that on major arterial streets like Kingshighway his staff continually has to adjust green time based on changing traffic patterns. "Ideally if you're going southbound on Kingshighway the light at Broadway will change before you pull up to it. That's the ideal situation but it's not always possible," he said.

At the intersection of Cape Rock Drive and Kingshighway, Hoernig said, the full spectrum of light possibilities is on a 110-second cycle. Of this time, the light shows green for northbound drivers 41 seconds and green for southbound drivers for 37 seconds.

This will frustrate some people headed north or south, but he says it has to be done to accommodate all the different turns people make onto Cape Rock Drive or into Arena Park.

So northbound drivers on Kingshighway who have just hit a red light at Broadway may very well hit another red at Cape Rock. It doesn't mean the system isn't working. It just means the system is handling a lot of well-travelled options.

"Traffic signals are basically a right-of-way device. And you only have so much green time to divide up," Hoernig said.

Officials had different answers to the complaint about waiting when no one is around. Green said it shouldn't happen because all of the city- and state-run intersections have monitoring systems that tell the signal when a car is waiting.

Cape Girardeau primarily uses video cameras, a monitoring system Green believes is the most reliable. "A lot of people think we're being nosey and seeing if they're running red lights, but all the camera does is detect whether or not there is a car there," she said.

MoDOT uses induction loops, which create a magnetic field above the pavement that the car breaks when it enters. This sends a signal to the control cabinet to give the motorist a green light. But the loops, which are approximately 6-by-30-feet, are only buried 3 to 4 inches deep. This means road construction work or pavement milling can put the devices out of order.

A malfunction would result in a motorist stranded at the intersection.

Hoernig said problems also arise when motorists don't stop on the loops. "It's sensitive enough to detect the metal in a bicycle, but it's kind of like stepping on a scale. If you take one step past it, it won't register your weight. That's why we tell people to pull all the way up to the white stripe," he said.

Green plans to tweak the way the city's signals are programmed. As of now there are no "soft recalls" on the lights. That means east-west traffic on a street like Broadway is not rigged to stay green as a default. If somebody makes a turn from one of the intersecting streets, Broadway stays red until a motorist triggers it.

"It just helps keep your main-line streets moving," said Green.

Both Green and Hoernig said it's difficult to give turn lanes a lot of time because they halt through-traffic. On city-run streets motorists are typically allowed to make left turns while yielding to oncoming cars. This is not allowed on MoDOT streets because of higher traffic volumes.

Addressing the complaint about the left-turn signal on Route K going into Cracker Barrel, Hoernig said it would be almost impossible to give motorists any more time.

"That is one of our most challenging areas because it is so close to I-55. We've got to try to keep traffic flowing on the main-line, and all the turns mean breaks in that flow," said Hoernig. "During lunch hour and especially in the evening when businesses, Doctor's Park, and the hospital are all letting out, it kind of overwhelms that whole section of town."

The city and MoDOT hope they have found a solution to the troublesome left-turn situation at the corner of Independence and Kingshighway. Workers are making the traffic islands further apart and will add another left-turn lane on Independence in each direction. This, said Green, will allow traffic engineers to cut down waiting time for both drivers on Independence and Kingshighway.

"The general public won't see a whole lot of change, but it will make traffic move smoother," she said.

tgreaney@semissourian.com

335-6611, extension 245