Overall, public transit ridership has grown to record levels (Figure 3-5-4/ Table 3-5-4: Public Tran sit Ridership). While the number of unlinked trips stayed about the same, passenger-miles advanced by 4.8 percent compared to the prior year (Table 3-5-6: Transit Unlinked Trips by Type of Service, Table 3-5-5: Transit Passenger-Miles by Type of Service).
Much of the increase in unlinked trips came from the three rail modes (commuter rail, light rail, and heavy rail subway) that, combined, generated about 15 percent more trips. Transit bus ridership, which accounted for 53 percent of unlinked transit trips in 2006, was slightly up (Table 3-5-6: Transit Unlinked Trips by Type of Service). With new commuter rail operations starting in northern California and New Mexico in 2006, new light rail service starting in North Carolina, and new routes added to several existing systems, passenger-miles for these two modes were up by over 9 percent each (Table 3-5-5: Transit Passenger-Miles by Type of Service).
New York City's Metropolitan Transportation Authority is by far the most active transit agency in the United States, handling over 2.8 billion unlinked passenger trips in 2006, dwarfing the nearly 500 million trips handled by each of the transit authorities in Chicago, IL, and Los Angeles, CA. The Washington, DC, Metropolitan Area Transit Authority, with 409 million trips, and the Boston Area's Massachusetts Bay Transit Authority, with 380 million trips, round out the 5 largest agencies. The 6.5 billion unlinked trips generated by the top 20 transit agencies represent about two-thirds of the nation's transit ridership (Table 3-5-3: Top 20 Transit Agencies by Un linked Passenger Trips).