16 As Petrol Prices Soar, Motorists Slowly Adapt As petrol prices rose in March 2008, motorists drove 11 billion fewer miles than in March 2007. Realising that prices were not going down, they adapted to higher energy costs. Motorists spend 3.7 per cent of their disposable income on transport fuels. How much we spend on petrol depends on the choices we make: what car we drive, where we live, how much time we spend driving, and where we choose to go. For many people, higher energy costs mean fewer restaurant meals, deferred weekend outings, less air travel, and more time closer to home.

Source: International Herald Tribune, 23 May 2008 a List and explain the elasticities of demand that are implicitly referred to in the news clip.

b Why, according to the news clip, is the demand for petrol inelastic?