With so many people hitting the roads this holiday, safety experts said they want to clear up some confusion about who to call when drivers get into dangerous situations.

Police are talking about drivers who fall victim to police impersonators. The fake police drive unmarked cars outfitted with lights that look like the real thing.

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Officials said anyone who is not sure if they're being pulled over by a real officer or an impersonator should call for help. However, they said, 911 may not be the best choice.

Pound (#) 77 is a feature on mobile phones that directly connects the caller to the nearest state police barracks in Maryland or Virginia.

The dispatcher on #77 can quickly find out if that unmarked car belongs to a real police officer or an impersonator.

"The impersonator is going to present an image of being legitimate and persuade the driver to get out of the vehicle," said Sgt. Russell Newell of the Maryland State Police. "If you get out, the situation could get bad."

One man described his ordeal with a police impersonator.

"It was not until after the entire incident that I even thought that he might not be a police officer," Josh Milner said.

Milner said that a couple of years ago, a man who said he was a Montgomery County police officer approached him. He said the man flashed what looked like a badge and asked if he'd been drinking even though Milner was coming out of a coffee shop with his family.

"In retrospect, of course I realized something must have been funny, but I was just scared," Milner said.

He could have called #77 to find out if any officers were patrolling the area, but some motorists said that might not get drivers on the road to the nearest department.

Police said #77 works best on the interstate.

"If a person off on a side road calls #77, (it will) connect to state police, which may not be patrolling the roadway at all," Newell said.

That's why the Cellular Telecommunications and Internet Association recommends that cell phone users remember just three numbers: 911.

"That's the uniform number to call," said Joe Farren of CTIA. "They shouldn't be distracted or confused. (The should) have the number in mind."

Police said there are other steps to be taken to avoid a dangerous situation.

Anyone who is being followed by an unmarked car with flashing lights should turn on their hazard lights and, at a slow speed, drive to a well-lit area with a lot of people.

"They'll recognize this as an attempt to continue moving until you find a safe location," Farren said. "Usually a law enforcement officer will automatically call for a marked car."

Police said drivers should keep their doors locked and only roll down their window enough to ask for identification or to ask for a uniformed officer. They also said drivers should never get out of their vehicle until backup arrives.

Police said drivers should make the call to 911 or #77 only for legitimate concerns. They said they don't want people calling or driving off just to get out of a traffic ticket.