The car's current technology pollutes air, land and water ; but its space effects , problems inherent in its concept , are more serious and intractable: its right-of-way and parking inflate exchange space and cities beyond sustainable levels, collisions are inevitable and spark an "arms race" for bigger "safer" cars that consume more space and resources. The Urban Sprawl generated devours the river valleys with Earth's most fertile climates and arable land, disproportionately damaging agricultural and freshwater resources.
The car system's resource appropriation is a black hole. It consumes an enormous amount of energy, labour and material in space monopolisation, collision remediation, the doughnut effect , inflated infrastructure costs etc. This is cross subsidised by generally raising prices and taxation. It takes an increasing proportion of world oil production, threatening to turn the imminent decline in oil production into a massive crisis. It diverts resources needed for eco-critical infrastructure and has negative social consequences: depriving other services of public funding, increasing the cost of living, stripping wage-earners and governments of their capital, increasing asset inequality and indebtedness and promoting mercenary behaviour by individuals and whole nations.
Car traffic increases the distance and time of walked journeys, the danger, toxins, turbulence, noise, and tarmac make outdoor life stressful, thus inhibiting walking. This brings a range of bad effects from an overwhelmingly indoor lifestyle: indoor pollutants increase illness, suppressed casual house-front interaction removes a whole dimension of social and economic life and reduces security, inadequate exercise causes obesity, bigger houses increase energy consumption. Cars are symbolic flagships of consumerism , and because they atomise human habitations and society, they also functionally multiply consumption and its consequent ecological and health evils.
The violence and resource demand of car culture repress real alternative transport ; while its preferred subtle or technological "fixes" are bogus alternatives ; they haven't and can't reduce car traffic or space demand or reverse the deterioration in environmental indicators. In short, of all the environmentally dangerous behaviours in a capitalist lifestyle, the car habit is the worst. A car ban is the one action that would address, at a meaningful scale and profundity of systemic effects, the Global Dangers : the environmental, economic and social damage generated by the civilization. It is, more than anything else, the touchstone of environmental survival, with it a sustainable human civilization is achievable; without it other actions probably won't be enough.
Only a ban neutralises the comparative advantage otherwise accruing to car users, defuses competitive emulation, empowers car non-use and defeats the hegemony and tragedy of the commons we are now experiencing. Good alternatives are available; but only to displace ; not complement, the car system. A good public transport and product delivery system is expensive, half as much as the car system; but for the resources, space and safety to be available, cars' threat and resource black hole must be removed. Ban the personal car in cities.