In industrialising countries, personal income has long been the main constraint on widespread car ownership. However, incomes are rising rapidly in the cities of many Asian countries, so that traffic congestion and air pollution are replacing income as barriers to higher car ownership. As a result, Asian car ownership levels, with the exception of Japan, are low, so that Asia's share of the world's car fleet is only about half its share of world income. Further potential barriers to higher car ownership are global oil depletion and supply security, which could well be the leading constraint within a decade, and regional/global climate change. More energy-efficient private vehicles, alternative fuels and propulsion systems, and more reliance on alternative transport modes have all been suggested as solutions to urban transport's resource and environmental problems, both for Asia and elsewhere. Particularly in urban Asia, hybrid vehicles can offer appreciable gains in both energy efficiency and emissions reduction, but at increased cost. However, if car travel was to become the dominant travel mode, any likely improvements in fuel economy from hybrid vehicles would soon be overtaken by rising vehicle-km. Another suggested approach is to use other hydrocarbon fuels, or fuels derived from renewable energy, including hydrogen. All these fuels, like petroleum, will in future either be in short supply, or have their own adverse impacts on air quality or climate. No foreseeable changes to vehicles or fuels appear capable of solving private car travel's fuel supply or global climate impact problems. Because of these various resource/environmental challenges, private car travel is unlikely to ever be the dominant mode in Asia's large cities. When the need for greatly increased land for vehicle movement and parking is also considered, a car-based urban future is even less probable. Instead, a combination of public transport, both electric rail and bus, and non-motorised travel appears to be the only feasible means of meeting the growing transport needs of Asian cities in a sustainable and equitable manner.