There were a few comment I received on my public transit post about what it costs to operate a car vs. the per km cost per person on a bus (approx. $0.35 per km per person for a bus, and I estimated about $0.30 per km based on my car - although that post has since been edited for length and content).
Anyhow, since some people questioned it, here is the estimated operating costs per km (2005 data) from CAA.
Obviously gas prices are slightly higher now. Keep in mind this is operating cost, not ownership cost. For the rest of this document: http://www.peoplescar.org/pages/documents/CAA_annual_driving_costs_2005.pdf