This in turn is likely to arise mainly from increases in trip length, and in trip purposes such as leisure, rather than the number of essential local trips to activities such as employment, education or shopping. The passenger sector is likely to be the more responsive to price changes, especially given the nature of journey purposes for which demand is growing. Conversely, modal diversion of freight transport has much less scope, since short-distance movement is already handled by road. However, for longer distance trips some diversion to rail is feasible and should be encouraged. There is also a role to be played by land-use planning to reduce the need for longer motorised journeys, for example in the location of shops.
Much less scope exists for reducing the rate of growth in freight demand.
While the tonnage of goods being produced may grow less rapidly than GDP, increasing specialisation of production leads to a greater volume of tonne-km being generated. Due to savings in production and inventory costs, a reversal or significant lessening of this process is unlikely in the short term, even if transport costs rose rapidly. However, scope should exist for greater efficiency within the road freight sector. The importance of different sustainability objectives depends on the weighting attached to various environmental outcomes. For example, if the global warming effect is the main concern, then reducing output of CO 2 and other greenhouse gases would be the main objective.