Has anyone had a similar careless driving charge?

I agree with the officer. Let me ask you this...how close were you to the vehicle in front of you? I am uming, pretty darn close since you hit the vehicle. I have always been told that when you are behind a vehicle, you should ALWAYS be able to CLEARLY see the vehicle's back bumper and tires. If so, then there really should have been no reason that your vehicle would have hit the vehicle in front of you.