LPG has only 66% efficiency when compared to gasoline
so it sort of evens out when you compare prices at the pump
gasoline is easier to handle
spill a lil gas (we call gasoline "gas" here not petrol) no big deal
spill a little LPG you may be goin to the hospital with freezer burns

i know i can handle LPG but John Q Public im not so sure
and the same guy refueling hydrogen - i shudder to think lol

i could have sworn in 2000 when i was in Arizona i seen on the news that Az had an alternative fuels program where the state reimbursed you for the conversion to your car - it nearly bankrupted the state - though i cant find the story in archives