Closed pass roads
In winter, passes can be closed, or driving conditions can be difficult (e.g. snow on the road). In that case it is recommended to travel by train instead. In some cases there are tunnels that remain open, or car-trains. Passes may also close all year round in case of severe weather.
Below is a list of popular passes and there general opening season. The map shows current conditions for all passes.
What if driving is not safe or not possible?
Switzerland has an excellent network of trains and other public transport. It's a safe, scenic and eco-friendly alternative to traveling by car. Please see here for all details.
Note that there are many places that can not be reached by car, either because cars are not allowed there, or because there's no road. A Swiss Half Fare Card allows you to save money on the tickets for trains and cable cars to such places. You will also save on boat tickets for the Swiss lakes.