Austin re-times dozens of signals to keep traffic moving

The change has increased green times by 40% (Dugan/KXAN)
The change has increased green times by 40% (Dugan/KXAN)

AUSTIN (KXAN) —  Cath Downs travels through the intersection at US 183 and Georgian Drive/Northcrest Boulevard three times a week to volunteer at the Austin Humane Society.

“I drive over here from my apartment,” she said, “it can get really, really busy and backed up.”

However, recently she says she’s noticed spending less time sitting at the light. “It’s gotten me here safer and faster and I think it’s a good thing.”

The change is part of Austin’s ongoing Signal Re-timing Program. Signal engineers determined that upgrading the intersection signal technology would result in more efficient traffic movements, adding capacity to the frontage roads where heavier traffic volumes exist.

The Austin Transportation Department modified the northbound and southbound Georgian/Northcrest left-turn signals to display flashing yellow arrows and modified the eastbound and westbound US 183 left-turn signals to display left-turn arrows. As a result of this change, the department was able to allow eastbound and westbound movements on the US 183 frontage roads to run green operations concurrently, which increased the amount of green time allowed to those two movements by an average of more than 40 percent.

For drivers, this means that through traffic on the frontage roads will experience a decrease in delays, and the left-turning movements and northbound/southbound Georgian/Northcrest through movements will not be negatively affected as green time remains unchanged.

This particular intersection was selected for re-timing because it has a unique traffic demand. The city says due to the lack of flyovers and direct connectors between Interstate 35 and US 183, all local traffic and freeway traffic must travel through this intersection to access the US 183 northbound main lanes. Additionally, traffic exiting from the southbound US 183 main lanes as well as traffic from northbound I-35 heading to local destinations must travel through this intersection carrying heavy volumes of through traffic. Local traffic to and from Northcrest and Georgian only contributes a small fraction the traffic volumes at the intersection.

Jim Dale with the Austin Transportation Department says intersections between two major roads tend to be the biggest challenges.

“We have a lot of traffic vehicles moving through. Pedestrians, buses and bikes. Those are out most challenging ones because we have to separate those different modes of transportation separately.”

Austin re-times about a third of its nearly 1,000 traffic signals every year, which includes signal lights and pedestrian hybrid beacons completing re-timing on all lights within three years. So far this year, 39 of 340 signals scheduled for re-timing have been completed. Dale says it’s critical to make sure they stay on schedule.

“We also have prepared a dashboard so we cam keep track of that progress throughout the year.”

Most recently, they’ve has also re-timed signals along Slaughter Lane between I-35 and Escarpment Boulevard. They say this has helped reduce travel time by 20 percent and stops by 37 percent.

They plan to re-time signals next at:

  • South Congress from William Cannon to Barton Springs Road
  • Lamar Boulevard from 29th Street to Morrow Street
  • US 183 frontage roads from IH-35 to Ohlen Road

The Austin Transportation Department says intersections that don’t require construction are the best choices for signal light re-timing.

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