Over the past decade, many cities around the world, though primarily in Europe, have put in place limits on the use of cars in their city centres, in some cases banning them outright. This has had several benefits, including reducing pollution and fossil fuel use, increasing walkability, and making it safer for bicyclists. It's also a great first step towards sustainability. This is an idea that needs to spread to more cities, and also be expanded beyond the downtown core to eventually include most of the area within city limits.
The limits on cars can take several forms. In some cases, cars are only allowed in downtown areas on certain days or between certain hours. In some cities tolls are imposed to discourage traffic, and in others they are simply banned. Legislation is currently being considered in many other cities, not just in Europe but across the US and Canada as well, to put in place similar restrictions.
Once limits like these are put in place, it becomes much easier to expand transit to meet peoples needs. This can take the form of subways, light rail, or buses. For many people, though, the use of the bicycle becomes a much more practical option. Today, riding a bike downtown in any major city can be very risky as many motorists don't pay attention, resulting in many accidents and deaths. With this risk removed, travelling by bike becomes much more pleasant and stress free, and one no longer has to worry about breathing in exhaust fumes. It also becomes safe for children to bike to school, or the library, or a friends house. In cities that have already banned cars, bicycle use has exploded.
In many cities, when transit is built today, it is done to accommodate additional passengers and relieve traffic. However, it is rarely done with the express purpose of replacing street traffic. Once traffic is banned from a downtown area, it becomes much easier to plan and build new transit. Over time, as transit options improve and capacity increases, the area in which cars are prohibited can be expanded. This can become an ongoing cycle as transit is slowly improved and the car free zone grows, until eventually cars are no longer permitted anywhere within city limits.
Of course, not all vehicles would be banned. Electric cars and trucks could be used for emergency services, deliveries, city works, transportation for the disabled, and other vital services. The road infrastructure requirements for these services though, is much less than what is required for millions of passenger cars. With less traffic, fewer and smaller roads are needed. Over time the city can be redesigned for walkability and sustainability, leaving in place a much smaller network of roads needed for essential services. This would also mean much reduced maintenance, lowering costs and energy use.
Alone with efforts to reduce car use in cities, though, we also need to improve transportation between cities and across the country. This can most easily done by expanding rail, which is several times more efficient than cars or trucks. An expanded rail network be used to transport cargo and passengers between many more cities and large towns, giving people a real alternative. Of course, rail can't connect all communities, so people will still need to use cars or buses in some cases, and cars will still be needed in many rural areas. Still, the vast majority of cars are currently used in cities and for long distance transportation between cities. By reducing this, we can dramatically reduce the total number of vehicles, bringing us much closer to a sustainable way of life.
Unfortunately, even while many cities are beginning to limit the use of cars, many third world cities are completely redesigning themselves for the car. In China, some cities have banned bicycles and they are busy paving across the country at the fastest rate in history, consuming enormous amounts of concrete, energy, and other resources. Aside from the obvious environmental damage and the carbon emissions generated, this is a very short-sighted approach. Even ignoring climate change, peak oil will make this infrastructure obsolete.
Cities in the third world should take the opportunity to build a more sustainable transportation infrastructure while then still can, instead of building something they will have to dismantle in the near future anyway.
We already know that banning cars from city centres is possible and that it works. It's been done in many cities already, and despite initial resistance in some cases, afterwards these policies have become very popular and have provided many benefits. Many similar plans are being proposed in dozens of cities around the world. Once in place, the idea simply needs to be slowly expanded, with new transit options filling the gap. Thanks to some early leaders, we know that car free cities really are possible.