(AOL Autos) -- That navy blue sedan behind you with the flashing blue light on the dash is probably a cop -- but it could be a creep using police paraphernalia to get you to pull over.

How to tell the difference? And what should you do if you're not sure?

In the United States, almost all traffic enforcement work is done by police driving one of the following vehicles:

• Ford Crown Victoria sedan

• Chevy Impala sedan (some departments also use the smaller Malibu and the Lumina sedans as well, though the majority in service today are Impalas)

• Chevy Tahoe SUV

• Dodge Charger

The problem is that these vehicles are also sold to civilians -- and it's pretty easy to dress one up so that it looks very much like an undercover police car. In fact, there are police supply stores that will sell everything a dirtbag needs to make himself look like the real deal -- right down to the uniform and fake ID. AOL Autos: Most popular sedans

Some departments also use unconventional cars for pursuit work. For example, the Ford Mustang LX 5.0 was very popular in the 1980s for speed limit enforcement; today, some departments use unmarked Camaro Z28s -- and even Corvettes -- for the same purpose. AOL Autos: Chevy Corvette vs. Nissan GT-R vs. Porsche 911

This is pretty scary, since we're all taught to obey the commands of law enforcement officers -- and when a police-looking car is trying to get us to pull over, every instinct tells us to comply.

Still, it's important to use your head.

First, have you done something to deserve being pulled over? If you've been driving within 5-mph of the posted speed limit and haven't broken any traffic laws that you're aware of, your guard should be up if all of a sudden there's an unmarked car on your tail with its lights flashing -- especially if it's out in the middle of nowhere and late at night. While radar traps are a reality, most of the time, we get pulled over for a reason -- and we know perfectly well what it is. So if you honestly haven't done anything wrong that you're aware of -- and the "officer" just appeared out of nowhere -- you're right to be suspicious -- particularly if you are female and traveling alone. AOL Autos: Used luxury cars for less

Second, if the vehicle attempting to pull you over is not a clearly marked police cruiser -- or a car or truck that isn't routinely used for police work (especially if it's an older/broken down-looking vehicle) and your "creep radar" is telling you something's just not right -- you should slow down (to indicate you are not trying to get away, in case it is a real police officer), signal your intent to pull over -- but only do so when you can find a well-lit, public place with other people around, such as a shopping mall parking lot.

Or, you can pull over immediately -- but keep your doors locked and only crack the window enough to pass your driver's license and registration through. AOL Autos: Fast, fuel-efficient cars

Third, get a good look at the "officer" and his credentials. If the "officer" is not in uniform, refuses to show you his badge -- or just flashes it briefly, so you can't get a good look -- keep that window rolled up and those doors locked tightly.

Ask once more to see his credentials. If he won't let you, tell the "officer" that you'd like for him to call another officer to the scene. This is your right -- and while it may aggravate the officer if he is in fact the real deal, it could save your life if he's not. A real officer will understand your concern and have no problem with calling a fellow officer (or supervisor) to the scene. There have been several case of women being abducted and raped by thugs impersonating police -- and most departments are very sensitive to people's legitimate concerns on this score.

Fourth, if the "officer" starts acting oddly when you ask to see his ID -- threatening you, behaving in a non-professional manner, pounding on your door, etc. -- seriously consider putting the car in gear and getting out of there. Tell the "officer" you are uncomfortable and that you will gladly follow him (or be escorted to) to the nearest police station.

If you have a cell phone, immediately dial 911 -- and tell the operator that you have been pulled over by someone who claims to be a police officer but that you think he might not be a real cop. Tell the operator exactly where you are -- and stay on the line. If it's a real officer, you'll know very soon. If it's not, the guy will almost certainly take off at this point. (Caution: Only take this step in a situation that clearly doesn't feel right as you risk an "attempt to elude" charge if it is, indeed, a real police officer. But again, better safe than sorry given the stakes.) AOL Autos: Top 10 off-road SUVs

These precautions -- and some common sense -- should keep you from getting anything worse than another traffic ticket.

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