COLORADO (KXRM) — While you may believe going 5 or 10 mph over the posted speed limit may be harmless, authorities in Colorado argue that isn’t the case.

Troopers with the Colorado State Patrol (CSP) are often asked at social gatherings or in brief conversations how fast someone can go over the speed limit before being pulled over. It’s a question they typically respond to with a rhetorical (but also serious) one: “What is the posted speed limit?”

In a press release last week, Colorado State Patrol warned of one of the reasons behind speed limits: being able to stop in time.

If you’re speeding, it could take you longer to react and brake should the vehicles ahead of you suddenly stop.

“Many motorists don’t consider the space they need to maintain around them when driving at high rates of speed. Two-car lengths is commonly practiced, but it is grossly deficient. A good rule of thumb is to have one car length per 10 mph traveled,” wrote CSP.

So, if you’re traveling 55 mph, you should be at least five car lengths behind the vehicle ahead of you.

“Motorists need to remember that it is not the initial act of speeding that kills you; the sudden stop at the end does,” warned CSP. “The faster you travel, the more distance is traveled, and your potential for a serious injury or fatal crash increases.”

Of the 2,860 fatal and injury-causing crashes investigated by CSP last year, speeding was found to be the top contributing factor in 685 of those crashes, followed by lane violations at 632 and impaired driving at 588.

As for why else to obey the speed limit, CSP said, “With so many people complaining about speeding and aggressive drivers, we all have contributed to the problem. If the average driver thinks it’s okay to go 5 mph or 10 mph above the speed limit, the risk-takers will go faster than that.”

So how fast can you really go before being stopped? The posted speed limit, CSP warns.

“Anything over the posted limit is speeding and subject to a potential citation.”