Should qualify my comment that providing the nat gas station infrastructure is not much of a challenge. That is its not much of a challenge in big cities where nat gas pipelines already exist, even the home owner can use his house gas line. The difficlty starts in rural travel in areas not serviced by nat gas pipeline. So for cars and trucks contained within or close to the city its not a problem. So for city fleet vehicles and commuter cars nat gas infrastructure is going to be easily provided. Certainly for taxi and delivery within a city it makes some sense. It also makes sense where air pollution is an issue. Having said this there could be some new safety issues with crash protection and as i said parking in confined areas. cng is going to be a growing part of the mix going forward. jmho.