A handful of frustrated commuters stuck in traffic on Lyndale Avenue during Thursday morning's commute contacted The Drive wanting to know what was behind the massive delays.

The answer is that two traffic lights were out of sync.

Minneapolis is in the process of upgrading its traffic control system and new stoplights were recently installed on a portion of Lyndale. On Thursday, two of the new control units that regulate traffic flow "lost contact with the mother ship" and were unable to communicate with the central traffic control computer system at the city's Traffic Traffic Management Center, said spokesman Casper Hill.

The lights at Franklin Avenue and another near Interstate 94 at the Lowry Hill Tunnel did have a backup system running, but those lights were unable to communicate with the other stoplights on Lyndale and thus were out of sequence.

"Those were critical for the morning rush," said Hill. The result was that some commuters spent 20 to 25 minutes getting from Lake Street to downtown Minneapolis.

The good news is that it was a temporary problem and it has been fixed, Hill said.

Commuters reported no problems on Friday.

Minneapolis is replacing most of its traffic light control units throughout the city this year and next. Lights in downtown were retimed and replaced this summer to improve traffic flow and give drivers more consecutive green lights. Work in south Minneapolis will be completed next spring.