I think the issue in the November storm years ago was the hills on Routes 280 and 80; drivers had a hard time getting up and there were accidents. I remember news footage of buses stopped on Route 3 westbound after leaving the Lincoln Tunnel; they were letting passengers off to use the bathrooms in the restaurants and gas stations along the highway.
Another unmentioned problem is that as NJ ran out of money they eliminated mechanical inspections for vehicles; they inspect for emissions only - so cars with bald tires, broken headlights/taillights, cracked windshields, etc. (which would have failed inspection in the past) are more common. You can still be ticketed for those things by cops, but you won’t fail inspection. In bad areas the car fleet on the road can look like you’re in Mogadishu...
The issue with that November storm a few years ago was that it was more severe than expected. It probably would have been OK if everyone who drove to work that morning was in a normal car or SUV, but every time I got caught on a suburban road at a standstill I could see that the delay was caused by a work van or rear-wheel drive car that couldn’t move up even the tiniest grade in the snow.