Transformation of the motor vehicle fleet has been an important feature of the world’s peak car phenomenon. Very few urban transport studies have explored such important changes in large urban cities. Using an innovative green vehicle datasets constructed for 2009 and 2014, this paper investigates the ongoing change in urban private vehicle fleet efficiency (VFE) in Brisbane. The spatial patterns of VFE change were examined with social-spatial characteristics of the urban area. The results showed that the social and spatial effect of VFE changes remain uneven over urban space. The inner urban areas have experienced higher level of VFE change, whilst people in the outer and oil vulnerable areas showed a low tendency in shifting to more efficient vehicles. The implication of VFE change for future household vehicle adoption was also evaluated based on a cost-benefit analysis of new vehicle technology costs and expected fuel savings for households that choose a fuel efficient vehicle. 

The results show that although current change in VFE can manage rising fuel costs, policies that rely on market-led improvement in fleet fuel economy are unlikely to quickly shift away from low efficient vehicle. Comparably, imposing a stronger national fuel economy target to the entire vehicle fleet would offer greater fuel saving opportunity for households and financial return to adopt a more fuel efficient vehicle. Such fuel saving benefits is even greater for a number of suburban areas where people use low efficient vehicle and drive longer distances annually. The results show that in a great number of suburbs, the economic wide upfront investments could be paid off from fuel savings if they were to adopt new and more efficient vehicles under a stronger VFE improvement program. Therefore, a stronger transition policy that offers more than market-led fuel adjustment to the existing vehicle fleets would generate quicker benefits to make vehicle upgrades cost-effective for suburban households. In addition, government initiatives to promote uptake of electric vehicles would further support achievement of the net zero greenhouse gas emissions target. The analysis has strengthened our understanding of the value of VFE change, and economic benefits of implementing a stronger national fuel economy strategy in Australian cities.