There are direct and indirect costs related to motoring, and some can be calculated only retrospectively.
Direct costs are: purchase price, taxes and registration, insurance, plus the direct running costs: fuel, consumables (oil, filters, tires, wipers, etc.) and maintenance (labor costs, brakes, servicing, bodywork repairs, damages etc.).
Indirect costs are the depreciation and cost of replacement. These can be calculated only retrospectively, i.e. after you have sold off the car and bought a replacement car after the mileage accrued. For example, a car bought for 1 million and sold for 500,000 while being driven 100,000 km will cost Rs 5 per km in depreciation, but a replacement car may cost 1.5 million by then. With the shrinking rupee in Pakistan, sometimes this may mean a buying price of 1 million, a selling price of 1.4 million after 200,000 km, but a similar class of replacement car may be 2.5 million by that time.
Thus, you start with a new car, and then end up with another new car, having driven a certain mileage.
All those expenses counted together will be the cost to drive per kilometer (or mile).