Why don't people carpool and use public transportation?

The City and County of Honolulu has one of the best bus systems in the country and for $40/month bus pass (unlimited rides), it's quite the deal, especially since I'm paying $3.40/gallon to fill up my tank every 5 days. Monthly parking at my office is $40/month, but I'm not complaining too much because my downtown colleagues spend anywhere between $100-$200/month for the ONE parking stall.

Still, because work's about 15 minutes away (no traffic), catching the bus would also mean I'd have to leave 30-45 minutes than normal to get to work in the morning and I'd also get home later. Because I tend to stay late at work in addition to meeting friends for dinner/drinks after work, riding the bus at night is not something I'd want to do.