MOUNT VERNON — A cop car in a school zone can slow drivers down, but Mount Vernon Police believe a sign can do the job as well — and without a hefty ticket.

The city of Mount Vernon has placed 13 solar-powered radar speed signs on roads near seven different schools within the past three years. When turned on, the signs display drivers’ speeds as they pass. Eight of the most recently purchased signs record the speed, time and number of cars passing.

They do not record specific vehicle information, such as license numbers.

“We’ve really started looking at this data, and we can see this is working,” said Dean Gilber, Mount Vernon Public Works inspector. “Even just (the signs’) presence. Tickets or not, people slow down.”

Mount Vernon Police Lt. Chris Cammock agrees.

“It’s definitely slowing people down, and people are doing it voluntarily,” Cammock said.

The city purchased two signs in 2005 for Lincoln School, then two for both Madison and Centennial Schools in 2006. Last year, it added three for Jefferson School, two for La Venture School, two for Washington School and one for Mount Baker.

Each sign costs about $5,000. The bill is split between the city and a state Amber Light Grant, Gilbert said.

The signs are usually only on from 7 a.m. to 9 a.m. then again at 2 p.m. to 4 p.m. to keep them unfamiliar to drivers.

“We don’t want people to get numb to these,” Gilbert said.

Cammock, said he sees the difference in driving from the new signs when he is unmarked as a police officer during his morning run.

“I’ve actually watched driver’s slow down when they see (the signs),” he said.

He believes simply displaying their speeds gives drivers the immediate feedback they need as a reminder to slow down. It also adds to a better alert system for a school zone.

With the data police collect from the radar signs they can monitor what times of day people speed, and patrol the areas if they deem it necessary.

For example, one sign recorded a car passing a school every morning at 7:30 a.m. going 50 mph.

An officer was sent to the area to watch for early-morning speeder.

“Almost to the minute, the girl was issued a speeding citation for going 52 mph in a 25 mph zone,” Cammock said.

Tickets for speeding between up to 5 mph over the speed limit are $189 and from 6 to 10 mph over the speed limit are $210.

• Tahlia Ganser can be reached at 360-416-2148 or at .