It’s not your imagination: Speed limit signs are starting to yell at you to slow down.
But don’t worry, they’re not telling the cops to give you a speeding ticket.
“Please let people know these do not read license plates. They are a radar device that collects speed data. There’s no camera,” said Sgt. Chris Remillard of the Dunbarton Police Department, who bought two flashing speed signs from the company TrafficCalm for his town using federal funds to cover half the price.
The units, such as the one currently attached to a 30 mph sign on Route 13 as it enters Dunbarton Center from the south, are smaller versions of flashing speed signs that have been around for years. Radar speed signs were once limited to large trailers that police departments would park alongside the road, but technology has shrunk to the point that now they’re the size of a computer laptop and can be clamped onto almost anything.
In the past three years, the state has provided funding for eight portable speed signs and four trailered signs, said Jeffrey Landi, who manages the grant program for the Department of Safety, giving federal Highway Transportation Safety Administration money to local departments.
Trailered signs cost around $10,000 compared to about $4,000 for the portable signs. The cost is usually shared 50-50 by towns and the state.
Landi said the signs have become more useful because they aren’t limited to nagging drivers. They also gather data about how fast cars are going and sometimes even how quickly they slow down, to help police find trouble spots and plan out enforcement details.
“They’re not new but they’re getting more sophisticated. Now they’re data-collectable,” said Landi. “Our captain is only funding these things now if they are data-collectable. We want to find out where the problems are.”
One thing they find: Virtually everybody speeds, at least a little.
Consider Gorham Pond Road at Gorham Drive, part of a popular cut-through in Dunbarton.
For the week of June 8 through June 16, a sign there recorded the speeds of 5,246 vehicles in a 30 mph zone, and just 437 of them actually drove at 30 mph or less.
In other words, 91.7% of all drivers were speeding. For most of the 15-minute collection periods in the sign’s database, everybody was speeding.
Admittedly, most weren’t speeding very much. Over the course of the week 3,628 vehicles, about two-thirds of the total, were going 39 mph or less, which many of us don’t really regard as speeding at all.
There’s a common belief that going up to 9 mph over the posted limit is somehow acceptable, as reflected in the ditty “If it’s 9 you’re fine, if it’s 10 you’re mine” attributed to a lyrical, and probably mythical, trooper. This belief, however, has no basis in law.
“That’s just something that people assume ... but speeding is speeding, period. We don’t want the public thinking they can go 10 miles an hour over the speed limit safely,” cautioned Landi.
The Gorham Pond Road database found that the average speed was 36 mph, that 15% of all drivers were going above 42 mph, and that the lowest speed recorded was 25 mph and the highest a hair-raising 75 mph.
This sort of information is useful for police departments trying to keep roads cafe, said Remillard.
“We try to pick locations that are known for generally high speeds, coupled with complaints from the motoring public as well as our observations,” he said. Most often the signs are placed in 30 mph zones, which tend to be residential areas that are more used by pedestrians and bicyclists.
“We deploy it from 5 to 10 days at a time, on a single battery charge,” Remillard said.
The signs are new for Dunbarton, he said, because the older signs were too expensive and hard to use.
“We’ve never had one before,” said Remillard. “Speed trailers require a lot of maintenance, you have to have tow-capable vehicles, you have to bring them back to charge them, they’re more susceptible to being struck or vandalized.”
There’s no question that the flashing signal slows drivers down, although it’s not clear how long the effect lasts. A host of studies have found that people hit the breaks when they see these radar speed signs but a 2010 report by the Federal Highway Administration could find no studies about whether it reduces crashes.
“As for the long-term deterrent value – the jury’s still out on that,” said Landi.
That’s okay by Remillard.
“If nothing else it’s a good reminder – ‘Oh, I’m going too fast. I need to slow it down,’ ” he said.