City to retime Downtown traffic lights

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August 4, 2003 // UPDATED 11:01 am - April 30, 2007
By: Scott Russell
Scott Russell

Year-end tune-up first in 10 years -- but drivers are bottom priority

They say timing is everything, but for the first time in a decade, city traffic engineers are going to retime Downtown traffic lights.

It's a traffic planner's version of a giant Rubik's Cube: in what order do you flip lights from green to red so everything lines up and drivers traverse Downtown more quickly?

The new timing system should be in effect by year's end, said John Hotvet, a city traffic operations engineer. Consultants at Short, Elliott, Hendrickson are doing the work, which is expected to cost $485,000.

"Theoretically, we should do a retiming plan every three to four years," Hotvet said. "We are a little behind schedule."

Light Rail Transit (LRT) provided the needed spark for the retiming project, he said. The city's consultant is working with the LRT traffic consultant to minimize delay on a per-person, not a per-vehicle basis. The model favors vehicles with lots of passengers -- LRT and buses -- over cars.

"We are maximizing it, more or less, for the high-occupancy vehicles, to make sure the buses and LRT get the maximum benefit out of it," Hotvet said.

Although consultants are not far enough along to know for sure, Hotvet predicted that even with LRT, retiming would cut travel time for the average Downtown driver.

The retiming planners start with traffic forecasts in the 2000 Downtown Travel Plan. Those numbers get stuffed into a complicated computer model that takes into account such things as bus stop locations, driving lanes per block, parking lanes, pedestrian counts, where Downtown parking ramps are, where vehicles enter and leave the system -- and then gives planners various measures to evaluate traffic movement.

That's Phase 1.

Phase 2 will take place a year from now, after the LRT is up and running for a few months and traffic patterns have stabilized. (Downtown LRT is scheduled to start in April 2004.)

Workers will do extensive counts of turning movements and pedestrian traffic at Downtown intersections to better refine the light timing plan, Hotvet said. Public Works would again retime the lights in spring 2005.