Lawrence's traffic engineer says getting green lights along 23rd Street is easy -- if you're driving in the middle of the night.
Drive west on Sixth Street from the Massachusetts intersection, and the traffic signals will turn green as you approach.
But head west on Ninth Street after the light at Massachusetts turns green, and -- unless you drive like Mario Andretti -- expect a red light at Vermont.
Lawrence's traffic signals are not timed to maximize drivers' frustration, says David Woosley, the city's traffic engineer.
But given the lack of coordination between most intersections and the different kinds of signal controls in use, some frustration is inevitable.
Traffic signals come in three varieties: fixed time, semi-actuated and fully actuated.
The city's downtown traffic signals, including those along Massachusetts, are fixed time, with "the same timing, day and night, 24 hours a day," Woosley said.
Actuated signals depend on pavement detectors and computers to control traffic flow. Semi-actuated means there are detectors on side streets but not the main street, so as long as there's no traffic on side streets, the traffic lights on the main street will remain green.
Fully actuated signals depend on detectors in main streets and side streets. But detecting traffic does not always mean coordination, as most drivers who have encountered the dreaded intersection of 23rd and Iowa are quick to discover.
Westbound traffic that stops at the Ousdahl traffic signal rarely reaches Iowa in time to make the green light.
The problem is a lack of synchronization between intersections, and consequently the 23rd-Iowa intersection signal is "like it's in the middle of a wheat field, just operating," Woosley said.
The city's only synchronized traffic lights are on Sixth at Massachusetts, Vermont and Kentucky, which are connected by wire, he said.
But the city is looking into synchronizing traffic signals on 23rd, Iowa and Sixth, which are state highways, with the assistance of the Kansas Department of Transportation.
"Timing traffic signals is not easy, and there's no perfect answer," Woosley said.