Just until the early 20th century horse & cart were literally the workhorses of transportation. The combustion engines and steam power - and later electricity replaced them slowly until the 1950s in most industrialized countries.

The question is what do we do when petrol becomes so expensive that a car or a flight is no longer affordable for the common man? How do we transport our food and other goods from the producers to our homes and shops?

Will electricity become the main source of energy or will be go back to proven methods of transportation like horse & cart?