The City of Lincoln utilizes seven different signal timing plans throughout a normal day. Traffic signal timing is based upon traffic volumes using the intersection during various times of the day. These volumes are obtained by someone actually sitting at the location and counting cars. The counts are then correlated to determine the highest one hour of traffic volume entering the intersection during the time of day that a particular signal timing plan will be in effect. In order to achieve coordination between signals, a common overall cycle length, which is the total time for all movements to receive a green display, is determined for use on a particular arterial or area of Lincoln. This overall cycle length is then divided into the individual movement times based on the traffic counts. Basically, the highest volumes of traffic receive the most time and so on. In this manner, the average approaching traffic is accounted for during the operating timing plan. Traffic volumes are dynamic, so there will be individual signal cycles where the volume of vehicles is greater than the average and not all will clear, however there will also be cycles where there are fewer cars that don't use all of the assigned time. In instances where timing adjustments are necessary, time is not just added to a movement, but moved from one movement to another. Care must be take so the adjustments which help one movement are not overly detrimental to another. Added into the mix are certain minimum time requirements, such as pedestrian crossing time, that may affect how the signal timing is utilized.

With all that said, we will review the assigned signal timing at 27th & Superior and make adjustments if possible. If you have noticed consistent stacking in that particular left turn movement during a definite time of day, please let us know. We do rely on drivers, such as yourself, who travel through areas regularly to keep us appraised of their experiences and assisting in maintaining as efficient a traffic signal operation as possible.

A project to install a U-turn movement at approximately 24th & Superior for eastbound traffic wanting to go back westbound will be undertaken this summer which should assist in reducing the volume of traffic using the eastbound left turn at 27th & Superior, particularly during the time period when school lets out.

Larry Jochum
City of Lincoln
Public Works Traffic Operations
(402)441-7711