why do cars only get 40mpg? could'nt we do better with all the technology we have?

[Nick]

cars that old didnt get the same mpg as sedans today...

the problem is that #1 cars safety requirements have skyrocketed meaning more weight, #2 the technology is already there, a few automakers have made cars that made over 100mpg, with the honda insight, there are quite a few claims of people getting close to 100mpg with a few minor mods. #3 i personally believe if we made cars that had mileage that high for daily use like cars trucks sports cars etc, gas would be $10 a gallon so the oil companies would still make their money.
#4 when that tech becomes mainstream, i bet oil companies would try to seize the patent so they would still make as much money as they do today.