This is partly a physics question, but has anyone come across any calculations for the ideal following distance at highway speeds to prevent rock strikes?
I assume rocks are lobbed upwards with negligible forward velocity, such that they follow a parabolic trajectory with respect to the car windshield. There may be two safe spots, one near the forward vehicle where the rock may clear your car (especially if it's a low sports car), and one far away where the rock has time to fall back to the ground before striking the following vehicle.
That's probably an oversimplification though, thoughts are appreciated!
Edit: adding some constraints - let's limit the discussion to pebbles which can chip windshields.
Edit 2: Perhaps we can treat this as an optimization problem and assume that the upper and lower limits of following distance are both safe. I suspect there is a sweet spot in the middle where you can safely pass under most rocks that are launched.