.......what will farmers and contractors just to name a few be able to work......
There will be small turbocharged diesel engines that will get much better milage than the present gas engines.
I have such a vehicle, a Sprinter van.. It has a Mercedes turbo diesel engine that gets 23 mpg at 70 mph cruise and 22 around town. It is three years old and not the current technology.
My big van gets the milage of a Honda CRV of the same age.