The issue isn’t really one of snow. It’s one of crowding. Our rush hr roads are now so fully, that they jam up at the slightest hint of an issue. Even a broken down lorry on the hard shoulder was enough to jam the M1 a few days ago, people just backing off a few mph, causing a concertina effect and bingo, stationary traffic! So add in a bit of snow, a few people being too cautious, a few being a bit reckless, and people generally taking just say 15% longer to complete any maneouver, and bingo, traffic chaos. When people post up pictures of say switerlands alpine passes, working fine with 5m of snow, that’s because they aren’t trying to get 220,000 cars/hr down that road at that time!!