Growing populations, expanding cities, environmental degradation, and economic pressures are creating a formidable challenge for transportation technologies and systems.
Everybody has ideas about how to solve traffic congestion, but the job is trickier than it seems, as a new report examining recent trends in computing patterns makes clear. Commuting in America III, published in October 2006 by the National Academies’ Transportation Research Board, finds that commuting patterns continue to evolve in complex and often surprising ways. The difficulty of accurately predicting the future presents obvious problems for policymakers.
Hydrogen cars, expensive oil, fuel efficiency standards, and inflation frighten those interested in maintaining and improving U.S. highways. All of these forces could erode the real value of fuel taxes that now are the largest single source of funding for highway programs and an important source of transit funding as well. Because of this worry, the Transportation Research Board convened a committee to carefully examine the future of the fuel tax.
Putting Maglev on Track" ( ) observed that growing airline traffic and associated delays were already significant and predicted that they would worsen. The article argued that a 300-mile-per-hour (mph) magnetic levitation (maglev) system integrated into airport and airline operations could be a part of the solution. Maglev was not ready for prime time in 1990, but it is now.
More federal support is critical to the future performance of the nation's highway system. The U.S. highway system faces many challenges in the years ahead, challenges that cannot be successfully addressed without new knowledge and innovations of all sorts. For example, how can highway agencies and their contractors reconstruct heavily used urban freeways while maintaining service and minimizing traveler delays and community disruption? Can the application of "intelligent" information and communication technologies reduce motor vehicle crashes, squeeze additional capacity out of existing highways, and improve the reliability of motor vehicle travel? How do roadways affect the natural environment, and what can be done to mitigate their impact? Can we develop affordable materials that will significantly extend the lives of highway pavements and bridges?
We now have the technical means to "solve" congestion. But do we have the political will? Traffic congestion is a vexing problem felt by residents of most urban areas. Despite centuries of effort and billions of dollars worth of public spending to alleviate congestion, the problem appears to be getting worse. Between 1980 and 1999, vehicle-miles of travel on U.S. roadways grew by 76 percent, while lane miles increased by only 3 percent. Average daily vehicular volumes on urban interstates rose by 43 percent between 1985 and 1999, from 10.331 million to 14.757 million. In a study of 68 urban areas published in 2001, the Texas Transportation Institute reported that the percentage of daily travel taking place during congested periods increased from 32 percent in 1982 to 45 percent in 1999; typical motorists faced seven hours per day of congested roadways in 1999 compared with five hours in 1982. According to the Federal Highway Administration, road delays (defined as travel time in excess of that at free flow conditions) increased by 8.5 percent between 1993 and 1997. Congestion also pollutes the air and wastes precious fuel.
Soaring personal vehicle use is producing great benefits but also potentially enormous costs. Motorization is transforming cities and even rural areas of the developing world. The economic and social benefits are enormous. It provides individual flexible transportation in urban areas and reduced manual labor and improved market access in rural areas. In the longer term, however, motorization may stifle local development, increase pollution, and create unprecedented safety hazards. Without careful attention to the motorization process, disaster looms for cities of the developing world--disaster from which the industrialized countries cannot be isolated.
Incorporating public transit into planning can help foster efficient land use patterns and create a more balanced set of transportation choices. Since World War II, two mutually reinforcing processes have characterized U.S. cities: decentralization and an increasing reliance on the automobile. Heavy investment in roads and other implicit subsidies of automobile use, combined with comparatively low levels of transit funding, have facilitated decentralized urban development patterns and inefficient use of land. These development patterns, which we refer to as sprawl, have made transit service unviable or inefficient in most suburban areas and many urban areas and have reinforced automobile dependence.
The effectiveness of new high-tech auto safety devices will depend on how drivers use them. Vehicle manufacturers around the world are spending large sums of money to develop sophisticated new safety devices. Anti-lock brakes were one of the first. Within the next 5 to 10 years, adaptive cruise control, collision warning, and vision enhancement systems are expected to become standard features on new cars, all in the name of safety. Governments, especially in Japan, Europe, and the United States, are contributing research funds for the development of these devices. Safety is the stated goal, but clearly economics is a major driving force. These devices will intrigue and attract car buyers.
Aviation industry growth and change will likely result in safety threats different from those of the past. Air travel in the United States has seen dramatic improvements in safety in the past 50 years. Through the cooperative efforts of manufacturers, airlines, governments, and others, pilots are better trained with the help of increasingly sophisticated flight simulators, aircraft are more reliable, navigational aids are improved, and flights operate with more in-depth and timely weather information. More recent evidence, however, suggests that the rate of progress in aviation safety has slowed or possibly stopped (Figure 1). The accident rate for jet carriers, which had improved steadily since jets were introduced, essentially leveled out during the 1980s and 1990s. Commuter carriers, which were required to meet the same safety standards as jets by 1996, have improved to the point where they now have roughly the same accident rate as jets.
Providing buyers with an overall assessment of a vehicle's crashworthiness would prod manufacturers to make better cars. What is the best way to make cars safer? As in the case of reducing environmental risks, the traditional strategy has been government regulation. Design standards have been used to require certain features that are implemented in certain ways, such as seat belts and air bags. Performance standards have been used to specify how a car must perform under test conditions such as a frontal crash. But there is a quite different strategy that would complement and extend these traditional approaches; one endorsed by a committee of the Transportation Research Board of the National Research Council (NRC). The committee, which I chaired, proposed a relatively simple approach: Give customers clear summary information on the safety of all new vehicles, make the underlying details available to all who want them, set up a research program to ensure that the information will improve over time, and then step back and let the competitive pressures of the marketplace force manufacturers to produce safer cars. The committee's recommendations are just as relevant today as they were when they were issued in 1996, perhaps even more so.
We must provide the elderly with easy mobility while protecting them from driving risks. For every mile they drive, people age 75 or older are more likely to be seriously injured or killed in an automobile accident than are drivers in any other age group except for teenagers. Contrary to common knowledge, the problem is not that the elderly as a group are involved in appreciably more accidents per mile traveled than are their younger counterparts. Indeed, up to age 75 there generally is no significant decline in the mental and physical abilities needed to drive a car without impeding traffic or endangering public safety. Even beyond that age, they are not appreciably more likely to have an accident.
We can reduce the health, safety, and environmental risks of light trucks without decreasing their advantages for consumers. Now that the media craze about the Firestone-Ford tire and sport utility vehicle (SUV) controversy is winding down, it's time to take a broader and more patient look at the impact that the growing popularity of SUVs and other light trucks is having in the United States. The good news is that the U.S. consumer has found that light trucks, particularly the SUV, offer an unprecedented combination of size, comfort, and versatility. The same vehicle can be used to go to and from work, fulfill carpooling responsibilities, haul cargo or tow boats on recreational trips, and take older children to and from college. The bad news is that sales of light trucks, which also include passenger vans and pickup trucks, have increased so rapidly that regulators and vehicle manufacturers have not devoted adequate attention to the consequences for safety and environmental objectives. Before discussing solutions, two rather extreme positions on this issue must be dismissed.
More creative use of existing highways and rights-of-way can help us build our way out of gridlock. All over the world, people are choosing to travel by automobile because this flexible mode of travel best meets their needs. But gridlocked expressways threaten to take the mobile out of automobile. Transportation planners predict that freeways will suffer from unbearable gridlock over the next two decades. Their conventional wisdom maintains that we cannot build our way out of this congestion. Yet the best alternatives that they can offer are to spend billions more on public transport that hardly anyone will use and to try to force people into carpools that do not fit the ways they actually live and work.
The government-industry partnership to develop a revolutionary fuel-efficient vehicle is in need of a midcourse correction.. On September 29, 1993, President Clinton and the chief executive officers of Ford, Chrysler, and General Motors (the "Big Three") announced the creation of what was to become known as the Partnership for a New Generation of Vehicles (PNGV). The primary goal of the partnership was to develop a vehicle that achieves up to three times the fuel economy of today's cars--about 80 miles per gallon (mpg)--with no sacrifice in performance, size, cost, emissions, or safety. The project would cost a billion dollars or more, split fifty-fifty between government and industry over a 10-year period. Engineers were to select the most promising technologies by 1997, create a concept prototype by 2000, and build a production prototype by 2004.