When I spent over an hour traveling each way to work, it was usually on the PA turnpike or Rts 81, 80, 322 etc. In Winter it doesn't matter how you try to maintain space. "Traction material" gets kicked up by all the vehicles. Being 30 carlengths behind another vehicle only means that there's a line of other vehicles passing you while kicking up the saltwater/grit mixture.
On highways where there are Jersey barriers in lieu of expanses of grass or woods, approaching vehicles toss stuff at you. Years ago I was heading East on PA283 and a truck coming West plowed through a patch of stone-filled slush and threw it over the Jersey barrier. Made an awful splat, but the glass was fine. When I got to Lancaster and stopped at a traffic light I noticed steam coming up in front. No damage to the grille but one fin of the radiator had a nick. Did a temporary solder fix that lasted forever