- Reduced damage to the evironment - one bus emit far fewer fumes than twenty, or even five, cars.
- Reduced use of fuel.
- Buses and trains are safer than cars.
- Reduced time spent on maintenance of personal vehicles.
- No need to find parking spaces at your destination.
"Public Transport is Good. The Advantages of Pooled Transport." by Vexen Crabtree (2007) will eventually contain some more discussion... for now, it's just a pagelet.