Amarillo breaks down the process of trouble with traffic

There are nearly 300 street signals in the city of Amarillo, and city traffic engineers have to follow a guide to help them develop the rules of the road, here that rule is called the 85 percentile.

City Traffic Engineer, Jerry Bird, said his team is really interested in traffic behavior and it helps them utilize the rule.

"We use the 85 percentile traffic volume, what that does is it gives us the p.m. peaks in both directions." he said. "We talked a little bit earlier about trip attractors and trip generators. So people going from their home to work in the morning, work would be the trip attractor, and the sub division where they live would be the trip generator. In the evening is would be the reverse."

Texas adopted the Manual on Uniform Traffic Control Devices as a guide in the 1960s. So it's not as simple as requesting a street sign and seeing it go up the next day, but it is worth calling in to state an issue.

"We depend on people calling in and telling us. Sometimes the police department calls in and says something is going on out here. We don't have the resources to check all of our signals everyday," Bird said.

City engineers can make most decisions as seen fit without going to a policy board, but if a complaint isn't resolved at the engineering level, it can be taken to a commission board for debate and public input.

City Traffic Commissioner, Mark Nair, said, "They can call the city and the traffic engineer will help them with their problem. If that problem isn't resolved, the way that they like it or if there is some other issue, they can always come to the traffic commission to appeal that."

A big issue for drivers is delay, and that's what traffic engineers call demand, meaning a particular place a lot of people need to get to at a certain peak of the day.

"The problem comes at intersections of course where demand is shared in two or more directions. So for example if you have a traffic signal at a four approach intersection and you give about half the green time to the north and south traffic and half the green time to the east and west traffic, you've cut the capacity of both road ways in half," Bird said.

Multiple studies have to be conducted before any recommendations or decisions can be made, and right now for busy intersections, it's a waiting game of research.

"It's a circular round robin of split phase movement to get traffic through," Bird said.