Toronto, east end, East York specifically, has sandy soil and with the spring thaw and melts there is sometimes sub tarmac washouts causing road holes sometimes big enough to swallow cars. I am fifty four and this has happen several times, lol. This does not happen every year and gennerally not caught on camera. Pot hole season is early spring. We also have real road issues with rapid temperature changes sub zero F to thaw and back can cause havoc in our climate. Dropping in a sink hole sure would wake you up eh?