They’ve seen the radar speed signs – and slowed down
If it is blinking and permanent, a sign slows drivers down.
At least that seems to be the case in Dakota and Washington counties, where permanent radar speed displays mounted beneath speed-limit signs have been prompting drivers to hit the brakes.
The signs — permanent versions of the portable electronic boxes that flash drivers’ speeds as they pass — started appearing in Washington County in 2004. Dakota County installed two on County Road 46 in Hastings in 2005. Then the counties watched and waited to see if drivers’ paces tapered off for good.
More than three years later, that seems to be the case. And Dakota County commissioners were pleased to hear it.
“I know the one on [County Road] 46 works,” Commissioner Paul Krause said, alluding to personal experience and drawing laughter from his colleagues during a presentation about the signs at a committee meeting Tuesday.
A study of the signs’ effectiveness in both counties found that average speeds dropped 7 miles per hour a week after the signs were installed and, three years later, are still down nearly 5 mph.
That doesn’t mean everyone is driving the speed limit, but “a five-mile-per-hour drop is significant,” said Kristi Sebastian, a traffic engineer with Dakota County. “As commuters [and] travelers go past these signs on a regular basis, they are consistently slowing down,” she said.
The signs, however, don’t come cheap. Dakota County paid about $10,000 for each by the time they had been purchased, installed and connected to electricity.
The cost prevents widespread installation, but Sebastian said the signs will probably be used in spots where speed has been a problem. A new sign will be going up in the spring on Hwy. 23 as it approaches Northfield. The County Road 42 curve in Rosemount could see the electronic signs installed this year or next.
“They’re very effective,” Dakota County Sheriff Don Gudmundson said, attributing the success to the alignment of the electronic speed reading beneath the posted speed limit. “When those are associated together, people slow down.”
And the intentional placement in “transition zones” where speeds drop as roads enter cities makes sense, he said. The signs in Hastings mark the drops from 55 mph to 45 and then 35. “Officers are more reluctant to issue a ticket in a transition zone because it feels more like you are entrapping people,” Gudmundson said.
The counties were among the first users of the electronic speed signs, but others report similar successes.
In Apple Valley, two signs on Garden View Drive alert motorists to a school zone. Police Chief Scott Johnson said the electric bill for each of the signs is about $7 per month. “It’s pretty cost effective if it’s going to slow drivers down,” Johnson said.