Wntrrn,

Buses are presently the most cost efficient alternative to single occupant motor vehicles, but adding on/off ramps contributes to gridlock, not smooth traffic flow, unless you mean ramps for buses only. What we are more likely to see is a bus only lane and the carpool lane, further reducing lanes available for single occupant vehicles. That is ultimately how people will be motivated to use a transportation alternative. When driving one's own car takes a good 10 to 15 minutes longer each way than using buses or trains or whatever, that is when people will switch.

As Hank points out, 84% (in Portland, but likely similar in many places) prefer to drive single occupant cars, and that is just what they will continue to do until it becomes less preferable. It becomes less preferable when it takes significantly longer or when it costs just too damn much, which varies according to individual affluence.

Hank,

I drive. I could take the bus by riding my bike to the bus stop, riding the bus, transferring to another bus, and then finishing off my commute on my bike to the office. Or I can just ride my bike the whole 10 miles. So why don't I? Because I don't have heavy traffic on my route, nor is it too expensive. Yet.