This is particularly apparent, as widespread use of electronic engine management systems tends to eliminate any opportunity to make 'ad hoc' repairs on a vehicle. Increasing technical complexity of vehicles inevitably forces up costs of maintenance in developing nations in the same way that it has done in the developed world. On a year-to- year basis, maintenance and replacement costs are considered to be a fixed cost. However, from the long-term sustainability point of view; these costs are variable and in all probability will rise. Table 2 below shows that general pressure on this cost is upwards.