ghost roads in Portugal

In Portugal there were built more highways rather than new train connections that could run on electricity.
The model of one car per person/family cannot work with a reduction of energy consumption.

As you can see we burn everyday 85 millions (in 2009) barrels of oil in the world:
Looks like 55% of this is used for transportation (in the US it is 70%).

Let us imagine that all this oil is not anymore consumed, since magically electric cars substitute all ancient engines. To make the equivalent energy in electricity, you would need 1.7 MWh (energy equivalent in one barrel) * 85 * 10^6 * 0.55 = ~79.5 TWh additionally produced by power plants per day.
The world produce ~ 20000 TWh per year that is 55 TWh per day:

Beside the energy conversion effort to electric (or hydrogen) cars, you would need to more than double the energy production (mainly done today with coal) just to let the transportation system work. Let us imagine that you find a 100% efficient car, you would need "only" ~24 TWh additional electricity (I am taking 30% as current efficiency), that is almost half of current electricity production.