Vehicles, a majority being tractor-trailers, were in a standstill at various spots along the roadway from the New Jersey State Line to Route 100.
Some drivers were in the traffic for 12 hours - since Thursday afternoon. Conditions began improving toward the early morning hours on Friday.
Police drove on the opposite side of I-78, honking their horns, to wake up drivers who fell asleep in their trucks.
"Drivers, wake up! Traffic's moving!" police shouted to drivers.
A viewer video sent into Action News showed a solid line of cars on I-78 near Route 33 around 7 p.m. Thursday.
Some drivers ran out of gas waiting for traffic to begin moving.
While traffic began to move on I-78 in Fogelsville, Mother Nature was not done with the wintry weather.
As Action News reporter Jeannette Reyes was speaking about the traffic conditions, a round of thundersnow hit the area. Action News quickly stopped the live report, until it was safe again for the news van to operate.