green transport

Cities exist to provide opportunities for interaction: working, shopping, playing, socialising, and so on. If all the opportunities we needed to reach were within walking distance of where we lived, then we could, well, walk to them. But mostly they aren't, so we don't. And that's no accident or quirk of fate, it's a logical outcome of city and transport planning, in response to evolving technologies.

Since cities started to be planned to make travel easy by car, transportation challenges have spun out of control. Cars have allowed cities to take shape in ways that make it harder to travel by any other means, with opportunities becoming farther apart and nonmotorised travel becoming more difficult not only because of the distances involved but also because roads and traffic are harder to navigate on foot or bike. And the traffic just keeps on growing, often at rates faster than the city's population.

It has become a losing battle to keep cities livable and sustainable when they are planned for the dominance of motorised transport, so some planners are starting to try and turn things around.

The transportation systems we see now in cities are a result of particular combinations of vehicle technologies, energy sources and spatial development patterns, which in turn influence travel patterns and the planners' responses with new infrastructure and services. That's a bit of a simplification, as each factor influences the other, and there are other considerations too, but the important thing is that transportation demand - the need to move - is a derived demand. We don't travel for the sake of it, we travel to gain access to opportunities, so any attempt to resolve transport challenges will require strategies that change where those opportunities are, and how we access them.

The negative impacts of transportation on the environment are a direct outcome of the combinations of technology, energy source and urban form prevalent in each city. My suggestion, then, is that green transport is some new combination of these factors that will result in reduced environmental impact. Exactly what that combination should be, and how it will be achieved, is open to debate.

Until recently, vehicle technology and fuel have not changed since crude oil first became available in cheap abundance. Only spatial form changed, generally in ways that supported - and were supported by - the private automobile. Now, in response to the twin challenges of climate change and looming fuel shortages, industry has put more effort into evolving towards cleaner technologies.

Unfortunately, these technologies won't be enough to qualify for my definition of green transport. For one thing, it will take decades to replace the existing world fleet of private vehicles, and the current crop of replacement vehicles (hybrids being the only serious contenders) only marginally reduce crude oil consumption and carbon emissions. Biofuel raises its own challenges, and only recycles carbon rather than reducing emissions. If the IPCC scientists and other analysts are to be believed, this is a case of too little, too late.

We need to focus just as strongly on ways to influence travel demand. This may be a combination of changing the design of roads and other public spaces to make nonmotorised transport easier, updating zoning practices to encourage greater mixing of land uses, increasing urban densities to make public transport more viable, reducing parking supply, establishing developments that are supportive of public transport (TOD, or transit-oriented development), encouraging green travel plans for ridesharing, and numerous other strategies.

Many governments are leaning towards the increased density approach, with improved public transport as their star strategy. They are generally not very successful in changing urban form, but a few have developed showcase mass transit systems, and others are trying to emulate them. If they were able to influence land use patterns to a greater extent, there would still be a challenge that few have grasped.

Mass transit is suitable for corridors of heavy travel demand, but not much else. Heavy demand happens where a large, dense residential area is linked by a transport corridor to a large area of employment, such as a city central business district. The millions of other trips that are dispersed throughout the city are very difficult to serve by any form of public transport, but particularly by rail or BRT (bus rapid transit). It will be very difficult to reduce the use of cars for those trips, unless a system is developed that is at least as good as in Toronto or London.

To make things worse, there is a contradiction in the planning approaches of many jurisdictions that are developing mass transit, in that promotion of mixed-use urban areas actually weakens the strong nodes that are the lifeblood of mass transit.

To be fair, the concept of mixed-use areas is intended to support short walking trips rather than public transport; but the application of mixed uses, increased densities, parking requirements and public transport are not always thought through in a coherent way at the metropolitan scale.

This presents a serious risk to the attainment of green transport. The greater risk, though, may be the inability of metropolitan authorities to exercise adequate control over all the factors that need to be brought together for a green transport strategy. Even in the context of strong policy, planning is often fragmented and stymied by political interference, uncooperative developers and unreliable funding.