It is important that the bus and truck tires used are winter approved and have the 3PMSF-sybol indicating that they have been tested and approved for winter usage. Having proper winter commercial tires on your truck or bus can be mandatory depending on the country; it is at least a necessity to stay safe regardless if you are transporting cargo or passengers. This is regardless if the snow is removed or not.
For main road clearance, you would mainly use a big truck with a snow plough and salt and sand spreader to melt the ice and snow as it falls. It is good to use special snow ploughing tires.