City “unsplitting” traffic signals

The Transportation Department is currently in the process of “unsplitting” traffic lights at certain intersections as part of its ongoing Traffic Congestion Action Plan. “When we unsplit the signal, we allow the left turns on both sides of the street to run together and the throughs on both sides of the street to run together,” Assistant Director Jim Dale told the Austin Monitor on Thursday. “This allows us to operate the signal more efficiently, and now we can reallocate the green time at the signal and improve the operations of the intersections.” Dale said the improvements have decreased current average delay times between 5 and 10 percent for the completed intersections, though that number can come close to 20 percent during peak times at some crossroads. Currently, about 10 percent of the city’s intersections are “split,” meaning that through and left-turn signals on one side of an intersection are more likely to run together. The city is nearly finished unsplitting its ninth intersection – at Burnett Road and Kramer Lane – and is working through a list over the summer of intersections that require relatively few resources to unsplit. Many of these intersections, Dale explained, require only road restriping and adding or rearranging signal heads at a cost of around $2,000. Others require more costly enhancements, such as purchasing right-of-way, and it is not clear what the plan is for those. “We’re starting with the simple ones first and just working down that list as quickly as we can,” Dale said.