Feb 03, 2009 — When big cities think about putting more fuel efficient, less polluting cars on the road, the first color that comes to mind isn't green -- it's yellow. There are so many cabs on city streets, they seem like a good place to start environmental initiatives. In New York City, the mayor has a plan to replace conventional cabs with gas-electric hybrids. But not all taxi drivers are thrilled about the plan. Samara Freemark talked to some of them.