The True Costs of Highway Congestion BY LANCE R, GRENZEBACK AND CLYDE

H ighway congestion is a daily phenomenon in all large metropolitan areas and a source of frustration and anxiety for millions of commuters and truckers. Incidents—vehicle accidents and breakdowns that tie up highway traffic-are a major cause of urban highway congestion. Once a concern limited to downtown areas of major cities, congestion is now a metropolitan-wide problem in medium, as well as large, cities. Since 1970, travel in urban areas has doubled, and travel on urban interstates has tripled. This growth in travel has outpaced the nation’s investment in highways, and greater congestion is the result.’ (See Figure 1.) Congestion is no longer limited to highways near downtowns; it has spread over the beltways that were once bypass routes. It is no longer a peak-hour problem; it has become a peak-period problem, spreading over as much as eight hours a day in large metropolitan areas. Congestion is creating bottlenecks on the highway system, and it is impeding the flow of regional and interstate freight, as well as local freight. Although congestion is recognized as a problem for commuters and motor carriers alike, information on the scope and cost of congestion is limited. A 1984 staff study by the Federal Highway Administration found that freeway congestion in the nation’s 37 largest metropolitan