I live in the boonies and I bike to work. :)
I would challenge your coworkers to really investigate biking - most peole rarely bike the same route they drive, so it may be shorter than they think. Half of most people's commuting time (by car) is often from sitting in traffic. Without it, the actual distance may not be that far.
And then there's the hybrid commute option. My H had a 35 mile commute (which took him an hour if he drove) when we lived in NC. He would drive part way (on country roads - so no traffic), park at a grocery store, and then bike the remaining 15 miles or so. It took him only 20 extra minutes than his car commute - but he got exercise and saved $ on gas (not to mention the environmental impact). Plus, he was a much nicer person on bike commute days! :p
Oh, and count me in the pro-gas-tax camp.

