Image: Senior man driving a car © Jose Luis Pelaez Inc., Blend Images, Getty Images

You're a careful driver and always travel at or below the speed limit, so you're shocked when you're pulled over on the freeway during your commute home.

The officer takes your registration and license, spends 15 minutes on his squad car radio making sure you're not an escaped serial killer, then brings you back your prize: a traffic ticket with "Below minimum speed" circled as your offense.

Wait a second. You can get pulled over for driving slowly?

That's right. Every state has a law on the books that says something along the lines of: "A person shall not drive a motor vehicle at such a slow speed so as to impede or block the normal and reasonable forward movement of traffic."

But does anyone ever actually get pulled over and ticketed? Absolutely -- and the ticket counts the same as any other violation against your driver's license and car insurance.

Making matters worse, the laws relating to slow driving and road safety can differ from state to state.

Some states specify a minimum speed limit for highway driving. In Florida, that minimum speed is 40 mph on highways with at least four lanes; Michigan's minimum speed limit on freeways is 55 mph. Iowa's law says that a vehicle that can't attain and maintain a speed of 40 mph can't go on the interstate system.

Additionally, laws in most states require a driver going slower than typical traffic flow to occupy the farthest right lane to allow other drivers to pass.

Safer to go with the flow

A couple of decades ago, Jim Gussler was pulled over while driving 60 mph in a 55-mph zone on Interstate 5 in California.

"Traffic was crazy and whizzing by me," he says. "It was the first time I'd been to California and the first time I'd encountered traffic like that."

He thought the officer was going to issue a ticket for driving 5 mph over the limit.

"Nope," Gussler says. "He politely explained that I was impeding traffic and needed to match the flow of traffic. He also explained that a slower vehicle was more dangerous than a speeding vehicle."

Gussler got off with a warning, but there's at least some research out there that supports that officer's claim.

In 1964, a U.S. government researcher named David Solomon wrote a paper on the subject of speed and crashes. He found that drivers going the median speed of all traffic -- not necessarily the speed limit -- had the lowest risk of collision. He also found that the crash risk increases more sharply at speeds below the average traffic flow than above.

"What that indicates is that law enforcement should pay at least as much attention to slow drivers as it does drivers going a few miles per hour over the speed limit," says Gary Biller, the executive director of the National Motorists Association.