jim is correct, the point that many anti-auto types make is that there are too many cars. and they are right.
regardless of the gains in eliminating tailpipe emissions more than 60% of the lifetime pollution of a car is in its manufacturing process and disposal. more and more cars require more and more space. water pollution from contaminated stormwater is increased and accelarated by expansion of roads.
the classist argument only goes so far when one considers the costs of a car based society. the costs we see are just a tip of the ones we dont. the clearly visible costs like purchase price, fuel, insurance, maintenance, and registration fees are dwarfed by, things like air & water pollution, military budgets to defend the oil supply, congestion costs, road building (often payed by non-motorists and motorists alike through sales taxes and other surcharges), public services like police, health care, and traffic-enforcement. the fact of the matter is that the working class, often regressively, is forced to pay for these things. people who dont own cars get a double shaft as the public transport systems are starved of funds.
the campaign for car free cities goes beyond simply doing away with the car. the redesign of cities to a more human scale, with adequate public transport, would make the doing away of cars a feasible option for many. for those who need to rely on mechanized transport, car sharing or shuttle travel can be a real option. the point is that the car is a horrible thing to organize a transportation system around.
aml