ford used to sell crown vic taurus and f150s in a cng/propane version bring this idea back in a bi fueled car were we can use regular gas and CNG. Cng price in my town is $2.01 equivalent to a gallon of gas. Cng burns cleaner and produces more power. the idea of it being bi fueled would be great because when on lond distance journeys there would be no worries of finding a CNG fill station.