Another snag at Montgomery County's traffic operating center messed up the traffic lights for thousands of drivers heading to work Tuesday, backing up major roads and giving commuters unwanted deja vu from a similar hitch just seven months ago.
Unlike November's mishap, when the computer that controls all county traffic signals crashed -- turning rush-hour treks into snail-paced crawls -- a clogged pipe gave drivers headaches this time, albeit brief in comparison.
County officials say an air conditioning unit stationed in the same Rockville room as the traffic computer leaked onto the floor, automatically shutting off the room's power. In the process, traffic signals desynchronized and reverted to a pace more suited for leisure Saturday afternoons.
Unsuspecting drivers were relieved when the power was restored and the system returned to normal around 9 a.m., officials said.
"We were fortunate that it was summer and traffic was lighter to begin with," said county spokesman Patrick Lacefield, comparing the delay to November's traffic catastrophe.
However, commuters were backed up at major corridors such as Georgia Avenue, Connecticut Avenue and Route 355 as late as 10 a.m., according to media reports.
A three-decade-old computer essentially sends signals to traffic lights throughout the county, making green lights longer during rush hour. It also synchronizes lights, minimizing the stop-and-go commutes -- to a degree -- that plague the Washington region.
When the Traffic Management Center flipped out in November, 750 traffic signals weren't switched to the proper settings for heavier traffic. And it spiraled into a traffic doomsday many Washingtonians will not soon forget, with nearby Metro delays compounding the problem.
"I got off easy this time," said Walt Benjamin, who couldn't "even remember" how many hours he spent on the road during the previous system failure. "You'd think we wouldn't have to deal with this again -- since it's 2010 and all."
The county is three years into a $35 million effort to ensure all lights can operate without the central computer. Lacefield said most of the traffic signals, however, are still tied to the outdated system.