Why would you pay to carpool to/from work instead of arranging carpool with a coworker, paying for your share of gas directly, and cutting out 1) the (future) middleman 2) the tax man?
Because the middle man is charging nothing, and its easier to use the middle man to find people that are good car pool partners by both desired arrival/departure time and where you are going to work from or going after work than trying to ask everyone around your work, and the tax consequences of accepting money to defray expenses don't change with or without the presence of the middle man.
If Waze becomes the "I need a ride " or "I'm coming to work, want me to pick you up?" handy-dandy awareness machine that is dynamic (key point) and universal (in everyone's pocket) then i think it becomes another management-benefit tool for the scores of workers that do not own cars in areas without transportation.
Before I go to my retailer I'll check waze to see if anyone I know needs a ride. Likewise when I drive home.
This is missing from our engagement with employees - a way to help with transportation.
I hope waze works the way I think it will.