Puzzler time. 

Okay, this one is old, but really good. 

I was 17 years old and I was driving on a gravel road at dusk in my white '65 Dodge Dart at a reasonable speed, around 90 miles an hour or so, because I was 17...

Then suddenly there was a big noise behind me, and the car bounced. It was obvious I had run over something. I quickly looked up in the rearview mirror and saw an object of some kind tumbling down the road behind me.

Because it was getting dark and because it was moving away at a speed of 90 miles an hour, the thing quickly receded into the darkness and I was not able to determine what it was that I had hit. 

I couldn't imagine how I could have run over something that could have struck the car so violently without me seeing it. I slowed down and pulled into the driveway of a farmhouse about a mile up the road. I got out and walked around the car. Everything looked fine. There didn't appear that there was any apparent damage to the vehicle.

After this little inspection I got back in the car and drove to the spot where the incident took place. And there it was, the object was still lying in the road. I stopped the car and got out. I looked at the object in the road, and then back at the car a few times. 

I knew that no further damage would result from my allowing the car to run. But I should get the car off the road as soon as possible. So I walked back to this object lying on the road and rolled it off to the side so that no one would run over it. I got back in my car and drove another mile to the house of some people I know and called the tow truck.

And the puzzler is, what was in the middle of the road, and what happened to the car?

Good luck.