An at-work driver is an employee whom uses a vehicle, even if just once a year, for work purposes.  Commuting from home-to-work, or vice-versa, does not apply.  Commuting from home to a location that is not your usual place of work is considered at-work driving.  Travelling to a meeting or taking money to the bank are choice examples. This could be in their own vehicle, a company owned vehicle, a cash-for-car scheme vehicle, or a pool vehicle. 

At-work driving is determined by the reason for the journey, and not the ownership of the vehicle.