Having seen, firsthand, several vehicles slap themselves out of grooves on the Glenn Highway, I have no doubt that it has caused a fatality at some point. I myself have had my car shunted laterally across and out of a rut during an extremely icy evening near Peter's Creek. Luckily it was late at night and everyone was doing 45MPH (intentionally!) and I was able to quickly correct to swing it back into the lane. Our asphalt quality is absolutely terrible.