Traffic signals at several intersections were knocked out of regular working order following lightning strikes in a brief storm on Wednesday night.
It took crews about 45 minutes to reset signals at 19th and Iowa, 23rd and Louisiana and 23rd and Haskell.
A police dispatcher said eyewitnesses reported seeing lightning strike the signals at 19th and Iowa on Wednesday night.
David Woosley, the city's traffic engineer, said most traffic signals have a built-in safety device, similar to a circuit-breaker, that is activated if lightning strikes nearby.
The device causes the lights to flash yellow and red automatically. The lights usually have to be reset, although sometimes they come back on line by themselves, he said.
``It's to prevent something from fusing together and having green lights in all directions,'' he said.