After heavy snowfall caused chaos on the main North-South axis on the Gotthard road route, the situation is improving, police say.
At least one lane is open in both directions and heavy trucks are being allowed to travel south at the rate of one a minute.
Snow on Monday caused the traffic to come to a standstill at times, with both trucks and cars blocking traffic because they were not prepared for winter conditions.
"An alarming number of cars were travelling on the motorway with summer tyres," commented Damian Meier, head of the traffic police in canton Uri.
The problem was accentuated because no sooner had snow ploughs cleared the road than it was covered by snow again.
Meier said that on Tuesday morning the situation had improved although there were still heavy snowfalls.
swissinfo.ch and agencies