This can be a bit scary if you are not prepared as the ploughs travel rather fast and it is easy to get disorientated. This is for your own safety.
Convoys can be between one and about ten cars, often with trucks bring up the rear.
Positions close to the plough can be difficult because of the snow thrown up by the ploughing operation. Snowplough drivers are at liberty to turn away any travellers they imagine may have difficulty in managing the strenuous journey, eg people who are not wearing winter clothes, people in cars that are not technically up to standard. The drivers are professional and have a great interest in not leaving you stuck in some snowdrift somewhere along the road. Keep a toarch, a tow rope and a snow shovel within easy reach. Cover the radiator grill as well as you can with cardboard or something similar.