Motorways are supposed to be the safest roads but they are actually quite dangerous as this thread proves. I've had a few incidents in my long driving career, none of which I could have avoided.
I had a piece of metal punch a hole in the car under the drivers seat in a Vauxhall Viva, and also a large flying remould tyre tread hit the front of my nearly new XR3 requiring a new bumper. bonnet headlight and grille.
The potentially worst was a large suitcase coming off the roof rack of the car in front and landing in the road in front of me. I couldn't swerve because of traffic on either side of me so could only brake hard and hit the suitcase and thankfully I wasn't travelling too close in which case the suitcase could have gone through my windscreen at 70mph.
I did claim off the car in fronts insurance for the suitcase incident but couldn't claim off anyone's insurance for the other two.