[Sburn]

Originally Posted by soutthpaw

But CNG makes a lot of sense for those 95% of single occupant vehicles commuting daily on Urban freeways.. Great way to eliminate our dependence ou Foreign oil in the short run.

I can see where CNG makes sense for buses and delivery drivers. I'm not so sure about mom's grocery getter. Conventional CNG tanks are heavy and take up a lot of room. One data point I found was that a CNG tank, equivalent to the driving range of 15 gallons of gasoline, weighs ~500 lbs empty. In contrast, a 35 gal gas tank, now plastic, weighs what, 30 lbs dry.

So any CNG vehicle starts off with a ~470 lbs weight penalty. In a small car, that's a big penalty in terms of the percentage of dead weight you're pushing around, which is going to hurt mileage. If you want to keep the mileage the same, or if you want to maintain cargo capacity, then 470 lbs. is going to have to be taken away from somewhere else in the car. It's not clear to me where you could take 470 lbs out of the average subcompact that wouldn't adversely affect safety.

I'm convinced CNG works for delivery trucks and buses because the added weight of the CNG tanks is only a small percentage of the total vehicle and cargo weight. I'm not seeing how it works in a single occupant daily driver unless somebody willing to sacrifice mileage, cargo/passenger capacity, or safety.