A couple years ago a fascinating thought experiment considered a decline in the use of gasoline cars due to the sudden rise of robo-taxis

http://rethinkx.com/transportation 

Though the taxis have not happened yet, many of the implications of the shutdown of gas cars are already underway:

“Oil demand will peak in 2020 at 100 million barrels per day by 2020, dropping to 70 million barrels per day”, resulting in oil prices at $25.40 a barrel. In the years since the oil price collapse in late 2014, the price had never been that low.

Current price of WTI: $22.75

A collapse of the shale oil industry: “In the U.S., an estimated 65% of shale oil and tight oil — which under a “business as usual” scenario could make up over 70% of the U.S. supply in 2030 — would no longer be commercially viable.”