I don't know how it's done on the West Coast, but here in New Hampshire they're not usually fixed in a way that will last a long time due to the fact frost heaves will simply bring them back again. Given the nature of the freeze, run plows over them, thaw, possibly refreeze schedule, the city uses cold patches all the time. I am no road engineer, but I'm guessing attempting to truly "fix" winter-generated potholes would simply move them around by 5 or 10 feet.