The capacity for suburban households to respond to a changing global energy context by changing their motor vehicle technology is examined. Transforming transport systems will make up a crucial element in policy and planning responses to energy and climate challenges. Government policy appears focused on a transition to more-efficient vehicle types or alternative fuel and engine types. Yet such policies have failed to account for the considerable social differences in household exposure to the costs of transport energy and the adaptability of households in altering their use of modes and vehicle types. Nor do such policies recognize how urban social structure, household social status, and automobile type intersect spatially within Australian cities. The links between urban social structure and composition of the motor vehicle fleet are examined to test whether the households that are most reliant on motor vehicles for transport have the financial capacity to rapidly alter their vehicle technology in response to changing energy prices and supply conditions. Australian Bureau of Statistics census data and motor vehicle registration data at the postcode level are used to compare socioeconomic status with the age, fuel consumption, and value of the suburban vehicle fleet for the Brisbane and South East Queensland regions of Australia. This spatial deployment of census and vehicle registration data is novel in the Australian context. It is argued that policies that focus on vehicle technology alone face a number of social equity hurdles as measures to overcome urban transport fuel security problems.