Why Traffic Cameras Shouldn’t Annoy You As Much As They Do

— -- Police get it: Speed cameras can be pesky.

“Nobody has ever really liked getting a ticket – whether it’s from me or from a camera,” Montgomery County Police Capt. Thomas Didone tells ABC News.

But it turns out those cameras can reduce fatal or incapacitating injury crashes by almost 40 percent on roads with speed limits of 35 mph or below, according to a study released today by the Insurance Institute for Highway Safety (IIHS).

Speed is a factor in about a third of fatal crashes in the U.S., the IIHS study says. But many commuters don’t realize how much putting the pedal to the metal can affect their safety.

“I don’t think the general public understands the consequences of speeding,” Didone says. “They don’t see the carnage on the highways that I do.”

If every county in the U.S. had enacted speed-camera programs like the one in Montgomery County, Maryland, where the study was conducted, they could have prevented around 21,000 fatal or incapacitating injury crashes in 2013 alone, IIHS projects.

Now equipped with more than 80 speed cams, Montgomery County has seen a 59 percent reduction in the likelihood of a driver exceeded the speed limit by more than 10 mph on roads with camera corridors.

And drivers are pumping the brakes even on roads that don’t have speed cameras.

“It's a good thing to have a speed camera right there so people can actually be more cautious, stop, slow down,” Montgomery County local DeAndre Wilson told ABC. “They snap real quick. You just see ‘em flash and you look around: Oh, they got me, they got me, yeah.”

But some locals are skeptical.

“I think the cameras are bogus,” Tiana Harris told ABC. “There's times where I get speed tickets where I'm like, there's no way José I was speeding, because I’m like a grandma driving down the road.”

To the doubters, Didone says: Officers routinely check the speed camera readings against other instruments, like handheld radar and laser guns. And if the camera malfunctions during setup or shutdown, the entire day’s readings are voided.

Meanwhile, using cameras frees up police to pursue other department safety goals – and unlike officers, cameras “never have to stop for coffee or a donut or take a bathroom break,” Didone laughs.

So next time you get caught speeding, instead of griping, think of the lives the camera may have saved -– and if speed limits are low, maybe ease off the gas pedal.

ABC News' Daniel Steinberger and Nate Luna contributed to this report.