The problem for a motor vehicle is this, when computing efficiency the car companies include the weight of the vehicle and it seems pretty good, except moving the vehicle is a result of moving the load, so you really should use the weight of the load without the vehicle and that makes the efficiency look abysmal. Because if I am moving 1300lbs of unneeded weight to move a 200lb load it can never be anywhere near efficient. Electric motors are more efficient, but where does the power come from? Currently, in North America there is very little spare generating capacity, if you moved all cars to electric power between now and Monday morning, you would fry the grid. It takes a long time to add generating capacity, the fastest is natural gas, it can take 7-10 years from concept to getting power, and that is only if the province/state wants it, and fast tracks the approval process. Oil fired has more opponents and takes a lot longer, you want nukes, start the process now, if you want to see power before 2041. Coal, I doubt you could get it through the approvals process these days, at least without a lot of conditions and few rail cars of payola.

The most efficient vehicle ever designed is the pedal bicycle. At a speed of 20km/h for an hour, the bicycle with 200lb load and 25lb bicycle, requires 66 watts. The most fuel efficient motor vehicle, according to Natural Resources Canada is the Toyota Prius at 3.7L/100km in the city. So to go 20km takes ..74L, a litre of gasoline provides 8760 watts for a total energy use of 6482 watts. That is 98 times as much energy to go the same distance. Of course it takes much less energy to collect the parts, make the bicycle and transport it to the dealer then it does a Prius as well.