What do I do if people are getting my car confused with someone who drives recklessly?

Within the past couple weeks, I've had at least 3 people think I'm the one driving like an idiot. I live in a small town and have a white Lancer, but there's a car I see every so often also white, but it's a Kia or Honda speeding so fast you can't see them. They've come close to side swiping me before, and go at LEAST 60mph on this back road with turns and hills.

Well yesterday just topped it off for me. I'm on a volunteer ambulance company, and our fire department has a Facebook page. The same car comes flying past me, with another car not too far behind it also in the opposite direction. I later notice the man following the idiot driver, was following me! He stopped at the top of my road, then drove off. I turned around and sure enough he was creeping back up the hill, getting a clear view of my ambulance plate. He later posts to the public fire department page, saying a white Lancer is going 70mph, passing on double lines, etc. I've tried contacting him telling him he has the wrong car, and he hasn't responded.

What am I supposed to do about this? I don't see this crazy driver often, and I've seen Troopers sitting on the side, but it's not a busy road. I'm afraid somebody is going to wrongfully accuse me of driving like this and report me to the police.

Get some blue painter's tape, and give your car some pinstripes and other markings temporarily. Heck, if I were you, I'd letter it with something, take a picture, and hand it to the police department in person. Since you drive responsibly, this would give everyone a chance to tell the difference. You shouldn't be stopped, because you're driving a different car now, and responsibly to boot.
Sooner or later this guy is going to get caught. For now, you need to give people a way to tell the difference between your vehicles. It's really that simple. Just a few pinstripes, so you are not technically changing the color of your car. And find a bright license plate holder too.

You can report what you know to the police. You can also take Rosalie's suggestion and alter the appearance of YOUR car. Aside from those 2 options, there's NOTHING you can do.

Note: It is 100% legal to change the color of your car. Technically, you would need to inform the DMV of the change, but that is not routinely enforced.