Commentary
About the data
Definitions
Data sources
Traffic congestion in urban areas affects the health of people, their quality of life, and the productivity of the economy. Household income and the ownership of passenger cars have increased, and the expansion of economic activities has been associated with road transport of more goods and services over greater distances. These developments have increased demand for roads and vehicles, adding to congestion and air pollution in urban areas—and increasing health hazards and traffic accidents and injuries.
The number of vehicles registered worldwide in 1946 was close to 46 million, with 75 percent in the United States. By 1991 this number had grown to some 600 million, with only 32 percent in the United States (figure 3.7a). During this period the growth of private cars substantially exceeded that of commercial vehicles (figure 3.7b), leading to relatively less use of public and mass transportation and thus to more pollution. The number of vehicles (excluding motorized two- and three-wheel vehicles) is expected to reach 820 million by 2010. In Iran, Kenya, Mexico, the Republic of Korea, and Thailand about half the registered automobiles operate in the capital city.
Congestion, the most visible cost of expanding vehicle ownership, is usually associated with the failure of urban transportation planning and, frequently, an inadequate road network. But expanding the road network is rarely the solution. The problem is that road users are heavily subsidized. Road users do not pay the full cost of building roads or of maintaining them. Until they do, urban traffic and congestion will continue to increase. In Asian cities, for example, rush hour traffic moves at an average of just 16 kilometers an hour—in Bangkok the average is closer to 9 kilometers an hour, and an average car is estimated to spend the equivalent of 44 days a year stuck in traffic (World Bank 1996d). Congested city streets exact a big toll on economic productivity.
How much does traffic congestion cost? In Bangkok the cost is about $400 million a year—the amount that could be saved just by making peak hour traffic move 10 percent faster. The hidden but all-too-real environmental tax on urban dwellers is high—the annual costs of dust and lead pollution in Bangkok, Jakarta, and Kuala Lumpur combined have been estimated at $5 billion, or about 10 percent of city income (World Bank 1996a). Another health threat associated with vehicles is particulate air pollution—the dust and soot from vehicle exhaust. This pollution is proving to be far more damaging to human health than once believed. Leaded gasoline causes about 90 percent of airborne lead pollution in cities. Yet in much of the world lead additives in gasoline are still used in alarmingly large quantities, especially in Africa. Lead poisoning does immense damage to children, affecting more than 90 percent of the population in African cities and 30 percent in Mexico City.
About the data
The data are compiled by the International Road Federation (IRF) through questionnaires sent to various national organizations. The IRF uses a hierarchy of sources to gather as much information as possible. The primary sources are national road associations. In the absence of such an association in a country, or in cases of nonresponse, other agencies are contacted, such as road directorates, ministries of transport or public works, or central statistical offices. As a result the compiled data are of uneven quality. In addition, the coverage of each indicator may differ across countries.
Definitions
• Vehicles per 1,000 people exclude buses.
• Vehicles per kilometer of road include cars, buses, and freight vehicles but do not include two-wheelers. Roads refer to motorways, highways, main or national roads, secondary or regional roads, and other roads. A motorway is a road specially designed and built for motor traffic. Except at special points, it provides carriageways separating the traffic flowing in opposite directions.
• Road traffic is the number of vehicles multiplied by the distances they travel.
• Traffic accidents refer to accident-related injuries and to deaths resulting from accidents that occur within 30 days of the accident.
The data in the table are from the International Road Federation’s annual World Road Statistics, except data for China, which are from Chinese statistical yearbooks.