Washington: What if There Were No Metro:
Impact on Downtown Traffic

The 2002 cordon counts conducted by the Metropolitan Washington Council of Governments (WASHCOG) indicate that much of the new ridership attracted to downtown by Washington's Metro (subway or underground) system has come from buses and car pool passengers (see Billions for Transit and More Congestion and Metro's Impact on Downtown Traffic). It might be wondered what would downtown traffic would be like if Metro had not been built. Comprehensively answering this question would depend upon a number of assumptions related to growth, market shares and alternative transportation studies, which would require considerable expense and effort.

However, one possible answer is provided by applying pre-Metro downtown travel market shares to the present travel volumes. Since the first section of Metro was opened, overall travel into the downtown area has increased nearly one-quarter. If transit, driver-only cars, and car pools were to have retained their market shares over the 1975 to 2002 period (and there had been no Metro), less than one percent more cars would have entered downtown during morning peak periods in 2002 than actually did (below). Thus, this set of assumptions would conclude that Metro's impact on downtown traffic has been insufficient to be perceivable.

Of course, other assumptions would produce different results.

Downtown is used as the area of analysis, because it is only to downtown areas that transit offers the potential to attract material market shares from automobiles in American or Western European urban areas. This is because only the core has a sufficient concentration of destinations and radially oriented, rapid service from throughout the urban area.