I don't know the exact "cost", which may be too complicated to calculate it, including car,maintenance,gas,insurrance, even tickets.... " ^. p9 H1 z2 n$ p) b# ^) N, k" x/ Q1 x
For me, I think car-pool is just to share part of gas "cost" and have some fun on road..... , O2 V: y3 W9 w0 B' `7 ~; Q$ R8 X: i
I usally charge passager 30 bucks for a trip.