The population of Third World cities. In metropolitan areas without effective public-transport systems, low-income households may have to devote up to one-fifth of their income on transport.
Those who own and use road vehicles rarely pay the full social and environmental costs generated.
Much of the health risk associated with road vehicles is borne by non-road users.
Road traffic accidents are a leading cause if death among adolescents globally.
Around three-quarters of all traffic accidents now occur in the Third World, even though the level of vehicle-ownership is higher in advanced economies. In Kenya, with 580 road fatalities per 100,000 vehicles in 1991, the death rate is thirty times higher than in the UK.
In India there are more fatalities (60,000) each year from road accidents than in the USA, yet if has one-twentieth the number of vehicles.
Most often it is pedestrians or cyclists who are killed or injured, and since it is generally low-income group who use these modes of transport, the costs of road traffic accidents are borne disproportionately by this section of society.
Traffic congestion combined with less efficient and poorly maintained engines, and higher levels if lead-based additives in gasoline, can also mean high levels of automobile-related air pollution, even when the number of road vehicles in use is substantially less than in Western cities.