Sustainability is the "buzzword" du jour in planning and environmental circles. Virtually every government has put in place a sustainability program of one sort or another, and we shouldn't be surprised that the concept has come to transportation policy.
Unfortunately, like its parent in environmental policy, sustainable transportation can mean many things to many people.
In Europe, unlike the U.S., many transportation policy analysts and decision-makers reach back to the 1994 definition provided by the Organization for Economic Cooperation and Development (OECD) as their benchmark: "Transportation that does not endanger public health or ecosystems and meets mobility needs consistent with (a) use of renewable resources at below their rates of regeneration and (b) use of non-renewable resources at below the rates of development of renewable substitutes."
The problem with this definition is that it completely ignores the fundamental role transportation plays in creating sustainable economic development and growth. Transportation systems and networks do not exist in and of themselves. They represent a crucial service-often public but increasingly private-that provides mobility. Moreover, like all services that provide fundamental economic and social value, they must increase the value they provide to society.
Too often, policy recommendations adopting a sustainability label implicitly accept a static policy making environment and focus on redistributing existing resources rather than thinking about how the stock of resources might be improved. This may be even more important in transportation than in other parts of the economy and society. Increased mobility, in fact, leads to greater economic productivity, allowing us to use existing resources more effectively and efficiently. Moreover, technology and innovation can easily make what now seems like a very scarce and limited resource obsolete within a generation.
Oil is probably the best contemporary example of this phenomenon. As the BRIC-Brazil, Russia, India, and China-economies grow at astounding rates, the demand for oil is likely to outstrip supply for a while, pushing prices up. Moreover, many energy analysts believe we have already met "peak oil"-that point where we no longer discover new reserves at a pace sufficient to keep up with current consumption. This geological reality has prompted many in the policymaking community to naively rush into heavily subsidizing alternative fuels such as ethanol since these rates of growth in the demand for oil are unsustainable. Many nations and cities have also started to embrace more draconian ideas such as cordon charges and other fees to explicitly limit customized travel options such as the use of automobiles.
This is unfortunate, because strategies that focus on reducing automobile use are not sustainable in an economic or an environmental sense.
From an economic perspective, efforts to push travelers and commuters into public transit inevitably have one of two effects.
First, it lengthens commute and travel times, reducing productivity and compromising the ability of our cities compete to globally. Our cities benefit from faster travel times, not slower ones. Moreover, faster travel times count for human resources, not just transporting capital goods.
Second, strategies that explicitly attempt to limit automobile based travel force people (and businesses) into higher densities. While higher densities (and more mixed uses) are not necessarily negative, the trade offs often include a much higher cost of living and lower mobility.
The key policy issue is whether these choices are made voluntarily-a demand side response that should enhance social welfare-or are forced through supply side limits-a response that compromises welfare by forcing citizens and businesses to accept a "second best" outcome.
The economies that focus on "first best" outcomes are the ones that will survive and prosper. In short, public policy focused on maximizing transportation performance will compete and be sustainable.
In addition, we need to recognize the critical role technology plays in changing the environment for resources use. Honda has already introduced a car for a limited test run that produces zero emissions. As gasoline prices increase, we are seeing the expected market shift toward cleaner and more fuel efficient vehicles. Moreover, we may easily see a world powered by nuclear electricity and wind turbines, making fossil-fuel based technologies that drive current transportation choices (and environmental concerns) obsolete.
Indeed, a transportation system based on renewable resources for its energy needs will meet the sustainable mobility goals of most developed nations. The key is to have the right technology in the right place at the right time. Now, as oil prices are increasing at rates unknown for a generation, we are seeing significant shifts through market-mechanisms toward alternative fuels.
Importantly, fixed-route alternatives are less likely to meet the mobility needs of a globally-competitive, 21st century city if we assume it becomes the backbone of the transportation network. Notably, global cities such as London and Paris still rely on the automobile for most travel in their urban areas. The automobile dominates because it provides flexibility and adaptability, two crucial features of a dynamic, competitive services based economy. A fixed-route transit-centric approach, as London is finding out, will increase travel times and ultimately degrade mobility for every one. Lowering mobility degrades both equity, by limiting access to jobs and products for workers and consumers, and economy by reducing productivity and efficiency.
Transit, of course, will continue to play a vital role in urban economies. It's a question of scale and the breadth of its application, not its viability as an important mode nested within the larger transportation network. Transit, however, cannot provide the back bone of a transportation network because our economic, social, and cultural needs are too diverse and dynamic. Transit will certainly remain viable, even profitable, as an alternative for certain segments of the population that place high values on hyper-urban environments (e.g., Manhattan, Central London, central Paris, etc.). These populations, however are a minority of the regional urban population, in wealthy nations. Eighty percent of Parisians live in the suburbs. In New York, just 1.5 million people live in Manhattan out of an urban region of nearly 20 million.
So, the automobile, and flexible rubber tire transit, is sustainable mobility.
If automobile-based travel is the core of a contemporary, flexible urban transportation network, we must thoroughly rethink the way this system is managed. Congestion is rising at dramatic rates. In the U.S., 12 metropolitan areas will have levels of congestion equivalent to, or exceeding, current-day Los Angeles unless policies are changed dramatically. Transportation policy must add capacity to allow supply to meet demand, but the new capacity as to be the right capacity, in the right place, at the right time. It also has to be managed efficiently.
Ultimately, road pricing will be the key policy reform needed to meet these transportation needs and ensure our transportation networks maximize mobility in a sustainable way.
Road pricing in the U.S. is being introduced in the form of HOT (High-Occupancy Toll) Lanes. HOT lanes are reserved for buses and other high occupancy vehicles but are also open to single occupant vehicles upon payment of a toll. The number of cars using the reserved lanes is controlled through the use of variable pricing (via electronic toll collection) to maintain free flowing traffic at all times even during rush hours. While occupancy rates vary in carpool lanes - some permit high-occupancy vehicle (HOV) rates of 2 or HOV-3 to ride free while others are free only to super-high vehicles such as van pools and buses.
The Reason Foundation first suggested in 1988 that the private sector could build supplemental congestion-relief toll lanes, using electronic collection using variable pricing which would keep the traffic free flowing even during busiest rush hours. The resulting project opened to traffic in 1995 in the median of SR-91 in Orange County California.
In 1993, another Reason Foundation paper examined converting HOV lanes that had been constructed around many US cities to HOT lanes by extending the concept of meeting the occupancy rate or paying a toll for single occupant vehicles. HOV lanes were originally intended to reduce traffic by getting drivers to share rides but many were underutilized and frustrating to drivers who could not use them. This conversion concept was dubbed "HOT lanes" a nomenclature that continues today and is supported by the US Department of Transportation. In the 1990's, the next three HOT lane projects were conversions of HOV lanes: I-15 in San Diego, California and I-10 and US-290 in Houston. To date, Colorado (I-25), Minnesota (I-394) and Utah (I-15) and Seattle (SR-167) have HOT lanes in operation. Other states are also implementing projects for congestion relief HOT lanes including Virginia (a $1.7 billion project to add HOT lanes near Washington DC) and Maryland near Baltimore.
When properly planned and executed, HOT lanes can be combined into a HOT Network of interconnected roadways that allow congestion-free travel throughout the region. There are currently no HOT networks in operation, but a number of metro areas (including both San Diego and San Francisco areas in California) include them in their long range transportation plans. Moreover, many of these HOT Networks can be self-funding if designed properly.
HOT lanes benefit not only those on the HOT lanes, but transit as well. For motorists, free-flowing HOT lanes give everyone an option of "congestion insurance" as an alternative to gridlock when drivers decide it is most important: to pick the kids up from daycare, make it to their soccer game or catch a flight. Variable pricing allows roadway managers to change the price to ensure sustainable congestion-free travel over the long term while also creating a sustainable flow of revenues to maintain and improve the facilities. By using pricing to discourage certain folks from traveling during peak hours, HOT lanes actually increase mobility. Orange County's experience is that the HOT lanes represent one third of the highway's lane miles, but carry over half of the traffic during the rush hour.
HOT lanes benefit transit riders as well. Because HOT lanes are free flowing and operating at high speeds even during rush hours, they can provide reliable guideways for express bus service. Transit agencies would prefer dedicated bus lanes. However with the value pricing keeping HOT lanes free-flowing; HOT lanes become the virtual equivalent of dedicated busways.
HOT lanes with variable pricing have become widely accepted as sustainable congestion relief technology in the U.S. The concept is support by environmental groups, local business associations and politicians of all persuasions. Implementing variable-pricing is a top priority of the U.S. Department of Transportation.
In conclusion, sustainable mobility means a lot of things to a lot of people. But, in the end, we need to focus on the ultimate purpose of a transportation system and network: improving mobility for people, businesses, services, and goods. We also need to be sensitive to the demands of high-end, services based economies that are adding significant value in the global economy. Most of all, we need to ensure we don't let naïve ideas about current resource use trap us into adopting policies that technology and innovation will solve on their own. Policymakers have bold new tools; most notably road pricing that will provide both the incentives and the financial wherewithal to make increasingly mobile urban areas sustainable environmentally, socially, and economically. Policies that compromise mobility are not sustainable in the long run.