In my case, gas cost had nothing to do with it. It was all the scarcity of parking spaces and the congestion of roads. My bottom line was that cycling was more convenient than driving. Even though I was not a recreational cyclist, I concluded that I should start riding to work.
The value of cycling is that it can substitute quite well for driving over short distances. Unlike carpooling, and mass transportation, it does not require any social or attitudinal changes.
Paul