Each car in the household is rated on a specific driver. The impact of an inexperienced driver is placed on one car in the household. If the inexperienced driver is the third driver in a two car household the new driver will be assigned as occasional to one of the vehicles. The impact is more significant if the vehicle is new and insured for liability, comprehensive and collision. Some people buy an additional older car so that the inexperienced driver will be assigned to that car. I do not understand the logic in adding two older cars.