Keeping a City on the Move

October 08, 2018

The last time traffic signal timing was updated in the City of Lincoln, it was the year of the Y2K scare. About two years ago, the city determined it was time to make some changes after city traffic engineers made a push for improvements. As a result, the city started the “Green Light Lincoln” initiative as part of its Traffic Management Master Plan.

One project that came out of that effort was to update traffic signal timing. The city tasked Olsson with making the traffic flow more efficiently along O Street (25th Street to Skyway Road), Antelope Valley Parkway (K Street to Military Road), and Normal Boulevard (Antelope Valley Parkway to South 56th Street).

Our Lincoln Traffic/Technology team relied on its strong partnership with the Kansas City Traffic/Technology teams to complete this project, which started with a large-scale data collection effort. We looked at the size of the intersections, distance the cars travel through them, posted speed limits, and pedestrian walking distances.

The next step included a lengthy analysis phase to determine proper left-turn phasing and red and yellow clearance intervals. This analysis allowed the team to maximize the green time for mainline traffic, update walk/don’t walk intervals for pedestrians, and recommend locations for a new component for Lincoln drivers – the flashing yellow arrow.

The flashing yellow arrow was incorporated as part of a massive infrastructure upgrade throughout the city. These upgrades were necessary to roll out the new timing plans. By doing these upgrades, we can maximize the amount of time the signal is green and select proper offsets to intersections as drivers progress down a corridor, both of which reduce travel time and stop delay.

Timing upgrades for O Street and Antelope Valley Parkway were deployed first, and the third corridor, Normal Boulevard, was deployed around Thanksgiving 2017. After the timings were deployed, the team drove the entire length of each corridor to document improvements and make adjustments.

The project team also documented before and after conditions by driving an assigned corridor with a GoPro on the dashboard and a computer with GPS tracking enabled. We drove the corridors multiple times to identify the time savings and to make sure each signal timing was deployed as planned. A video log was used to generate a side-by-side comparison of before and after conditions. The city also tasked us with providing messaging to help educate the public on the upgrades.

This project brought a few challenges with it, such as working with the other consultants when we had overlapping sections. Another challenge was riding the learning curve as we developed methods for the city as it made the system uniform. In the end, the project was a success, and the challenges we encountered allowed our communication and coordination skills to grow stronger and deeper along with our relationships with the other consultants and city personnel.

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