Hybrid vehicles are close to ideal for the job of NYC taxi. NYC taxi's are often idling and very often braking. Hybrid cars take advantage of braking to reclaim energy, and avoid an energy penalty for idling. In addition, electric engines have a flat torque line, ideal for gunning it from one red light
to the next.
So how do you get NYC cabs to switch? Well, we can do this *and* raise revenue for NYC at the same time. "Green Cabs" (as opposed to yellow cabs) would be allowed to charge a slighly higher metered rate. Perhaps a 50 cent surcharge. So the first step is accomplished, the taxi drivers are incented (plus they save money on gas).
Now the cab companies (the guys that own the medallions) can charge more to rent a green cab. (I think that the going rate is about $150 to rent a yellow cab for an 8 hour shift).
Now the city can charge a higher tax on "green medallions".
The consumer gets the short end of the stick here, but it ain't all bad. Many people I have polled say that they would pass on the green cab in order to save money. Some people would be willing to pay a higher amount for the sake of the environment. During rush hour, folks would gladly pay a premium to get the car.
Possibly, cabbies could opt to charge the lower rate during off-peak times and indicate this with a special yellow light on the cab so that they don't lose fairs. Basically, we open up a small window of price competition.
In any event, incentives on the supply side all but ensure that green cabs would all but replace yellow cabs within 3 years.
One hurdle is trunk space. NYC cabs require big trunks for airport hauls. So a modification to existing hybrids would be necessary but probably not a big deal if you are purchasing in fleet quantities.
Of course the government could always simply "mandate" cleaner vehicles, but I think that this idea would ruffle less feathers. To the best of my knowledge there is no active lobby for "taxi-cab rider rights".