I don't know what will happen to the price of lpg, here in the states it's very gray, depending on the state you may only pay the regular sales tax on it with no road taxes, the price is always at least $1/gallon less for lpg.

the efficency issues are mostly because of the dual fuel setups. I've gotten about 30mpg on the highway going as 80+ mph, not too bad, my city milage is crap. I think I can tune the city milage to be better.

I guess LPG is not for everyone. Unless i get a way bigger tank, 20gal vs 8 which is what i'm working on now, it's of limited usefulness. I drive around and it's about the same price per week as petrol. the maintenance costs are much lower with not needing oil changes very often, so i bought a few bottles of expensive oil and it'll be in there a long time. ( if you have an old tired engine, then you'll be waiting a while to see oil stay clean. )

there are issues with LPG, but i think it's because we choose to see them, rather than petrol's perceived safety.

I don't plan on going back to petrol unless something unexpected happens.

I had thought very serios about converting my datsun to dual feul , the only reason I have'nt is cause here in the southern U.S. there are not any LPG pumps at any gas stations .