Kevin French knows exactly what he'll be doing March 11.

"On that Sunday morning, I plan to sit at home with my laptop and a cup of coffee and make the change," he said.

French is traffic and transportation engineer for Jefferson County and "the change" is adjusting traffic signals for the switch to daylight-saving time.

On that same morning, traffic engineers in other parts of metro Denver also will be checking their signals.

That's because stoplights, like computers, VCRs and other devices, think daylight-saving occurs on the first Sunday of April, the traditional date to "spring forward." It's earlier this year because a 2005 federal law moved the date as an energy-saving strategy.

Traffic crews are poised to change the internal clocks in traffic signal systems March 11 - an easy job for some, not so easy for others.

Traffic signals on major roads give a longer green time to the rush-hour direction of traffic.

Without reprogramming, signals would remain on standard time and wouldn't start rush- hour timing until an hour into the commute.

For some agencies, like French's, the tweaking can be done with a few mouse clicks. For others, it means visiting numerous older signals to change out a chip in their controller box.

CDOT has 340 signalized intersections in the Denver area. Some can be adjusted temporarily from a central computer, but eventually each one will need a personal visit.

Denver city traffic engineers started taking stock of the problem late last year.

"We're not anticipating any problems, but I still have staff scheduled to come in that Sunday morning to make sure we can do any necessary changes," said Matt Wager, a Denver traffic engineer.

About 700 of Denver's 1,240 signals can be reprogrammed from a central computer. The others have to be changed by hand.

Dave Baskett, Lakewood's traffic engineer, said the city controls 120 signals on the major corridors from a central computer. About 55 others on side streets have to be manually changed, however.

"Probably another 30 if you count the school zone flashers," he said. The school zone signals are programmed for each school's schedule.

"We'll have a big effort to go out and reset them by hand," he said.

It's the same in Aurora, with 99 school zone flashers. But, said traffic manager Dick Havercamp, all but four of Aurora's 300 signalized intersections can be updated from the comfort of the traffic control center.

"We can speak to all of them and say, 'Change daylight-saving time from A to B,' " he said

Even after March 11, the work isn't over. Traffic officials have to watch on April 1 to make sure the signals don't jump ahead another hour.

And because daylight-saving time will last a week longer, they have to watch again the last Sunday in October.

flynnk@RockyMountainNews.com or 303-954-5247