Over the past year, transit ridership has risen and that is a good thing. At the same time, driving has declined, due to both higher gasoline prices and the economic downturn. Some analysts have implied that people are giving up driving and using transit instead. An analysis of just released transit and urban roadway usage indicates no such thing. During the fourth quarter, the transit increase from a year earlier represented just 0.7 percent of the driving decline. This is even lower than the 2 to 3 percent figures registered in the first through third quarters. Of course, the principal reason why people do not substitute transit for driving is that it is not available for the overwhelming majority of urban trips.
The latest data is available at: http://www.demographia.com/ut-hwytr2008f.pdf.