For years, mass transit has been promoted in the United States as a substitute for the automobile and a solution for metropolitan traffic congestion. A new report by the Brookings Institution shows that these claims have been highly exaggerated. According to the Brookings analysis, only 7 percent of employment locations in the top 100 metropolitan areas is accessible by transit to the average resident in 45 minutes during the morning peak hour (when transit service is most intense). While Brookings did not examine 30 minute access, which would be a better indicator of the usefulness of transit to the average employee, since one half of US workers reach work in 22 minutes or less. Based upon the Brookings 45 minute estimate, it seems likely that 3 to 4 percent of metropolitan employment would be accessible by transit in a 30 minute period.
The Brookings access indicator is significantly different than the normal transit "coverage" indicators, which yield higher figures. Coverage indicators simply measure whether transit service (such as a bus stop or rail station) is available within walking distance, without providing any indication of whether particular locations can be reached from the bus or rail stop or, whether such locations can be reached in a reasonable period of time. For people needing to reach jobs that might be located virtually anywhere in a metropolitan area, coverage indicators are largely meaningless. Access time is all that counts.
To expand transit services to materially increase transit job access would require inconceivably high expenditures.
This issue is described further in "Transit: The 4 Percent Solution" at http://www.newgeography.com/content/002251-transit-the-4-percent-solution
Demographia Observations 