New York City adding MORE hybrid taxis

Can hybrid cars save money, many ask. Yes, especially if you are a New York taxi driver. Many hybrid vehicles, such as the Ford Escape hybrid or the Toyota Prius hybrid, often achieve far better results in the WORST driving conditions. Consequently, in New York City, hybrid taxis can "get double the gas mileage of traditional cabs and generate less pollution" (more). Since congestion is the norm for most American drivers and congestion is predicted to increase significantly in the next few decades, shouldn't the fuel economy standard be focused on city driving, not highway driving?