The 18 years of data presented in this report document the growth of congestion levels on the major roads systems of 68 U.S. urban areas. The data provide a relatively easy to understand view of an issue that is widely discussed, but perhaps not as well understood. The data speak to increasing traffic demands and a transportation network that is not expanding as rapidly, and hints at some of the other causes of traffic problems. Major transportation system improvements require time for planning, design and implementation, and often a significant amount of funding as well. Communicating the condition and the need for improvements is a goal of this report. The decisions about which, and how much, improvement to fund will be made at the local level according to a variety of local goals, but there are some broad conclusions that can be drawn from this research database that apply to the areas studied. Congestion is growing in areas of every size. The 68 urban areas in this report range from New York City down to those with 100,000 population. All of the size categories show more severe congestion that lasts a longer period of time and affects more of the transportation network in 1999 than in 1982. The average annual delay per person climbed from 11 hours in 1982 to 36 hours in 1999. And delay over the same period quintupled in areas with less than 1 million people. Congestion costs can be expressed in a lot of different factors, but they are all increasing. The total congestion "bill" for the 68 areas in 1999 came to $78 billion, which was the value of 4.5 billion hours of delay and 6.8 billion gallons of excess fuel consumed. To keep congestion from growing between 1998 and 1999 would have required 1,800 new lane-miles of freeway and 2,500 new lane-miles of streets — OR — 6.1 million new trips taken by either carpool or transit, or perhaps satisfied by some electronic means — OR — some combination of these actions. These events did not happen, and congestion increased. Road expansions slow the growth in congestion. In areas where the rate of roadway additions were approximately equal to travel growth, travel time grew at about one-fourth to one-third as fast as areas where traffic volume grew much faster than roads were added. By themselves, however, additional roadways do not seem to be the answer. The need for new roads exceeds the funding capacity and the ability to gain environmental and public approval. The answer to the question "Can more roads solve all of the problem?" doesn’t lie in esoteric or theoretical discussions as in practical limitations. In many of the nation’s most congested corridors there doesn’t seem to be the space, money and public approval to add enough road space to create an acceptable condition. Only about half of the new roads needed to address congestion with an "all roads" approach was added between 1982 and 1999. And the percentage is actually slightly smaller in the smallest areas — where one might expect roads to top a shorter list of improvements than in larger and more diverse urban areas. The "Solution" is really a diverse set of options that require funding commitments, as well as a variety of changes in the ways that transportation systems are used. The chosen options will vary from area to area, but the growth in congestion over the past 18 years suggests that more needs to be done. More roads and more transit are part of the equation. Some of the growth will need to be accommodated with new systems, and some older system elements expanded. More efficient operations can derive benefits from existing systems. Some of these can be accelerated by information technology and intelligent transportation systems, some are the result of educating travellers about their options, and providing a more diverse set of options than are currently available. The way that travellers use the transportation network can be modified to accommodate more demand. The longer periods of high travel volume (the "peak period" instead of one "rush hour") already accomplish this, but there are ways to give incentives and improve conditions for working, shopping and a variety of other activities as well as improving the travel situation. There are a variety of techniques that are being tested in urban areas to change the way that developments occur - these also appear to be part, but not all, of the solution. Some of these have been labelled "smart growth" actions, but most are just familiar methods of arranging land use patterns to reduce the use of private vehicles and sustain or improve the "quality of life" in urban areas. The typical suburban development pattern will be part of most cities for many years, but there are a number of other patterns and modifications to existing developments that make transit, walking and bicycling more acceptable for some trips. Improving the reliability of the transportation system is an important aspect of the programs in most large cities. Identifying and clearing accidents and vehicle breakdowns, addressing construction and maintenance activity impacts on congestion and providing more reliable and predictable travel times are goals for congested corridors. Future reports will examine the impacts of these activities and their role in urban congestion as it relates to moving both people and freight. This year’s report is the product of a co-operative arrangement between the Texas Transportation Institute and 11 state transportation agency sponsors. The Urban Mobility Study continues to research new data and new estimation methods to measure and communicate transportation issues to a range of audiences. More information is available on the study website: http://mobility.tamu.edu/. (A)
Samenvatting