2nd ave subway is a response to pop growth in the Bronx.  If I remember my numbers correctly, the green line carries 1/3 of the daily subway users.<p>When I rode the red lines, I worried about getting a seat.  When I rode the green lines from the express stop at 86 and lex, I worried about getting on the train.<p>Also, I think you forgot to mention the <i>enormous</i> subsidies to car ownership, from free parking to general tax money used for roads to wars to secure oil supplies.  Thus the marginal cost of driving is far under the average cost.  While public transit is subsidized, it isn't subsidized anywhere near as much.