As usual, don't forget the low-hanging fruit of the early 80s: easy gains in vehicle efficiency and the shift away from oil to NG for electrical production. An ad hoc crash program to shift to alternatives won't necessarily be as simple to implement, and rationing is a very likely possibility.
The link between GDP and VMT is much closer and more instructive. Here's a graph of vehicles in the US juxtaposed with number of commuters still driving solo, and the total HEV sales in the US to date (592k):
As you can see the bar for the HEV sales doesn't even register thick enough to display the proper color. HEVs won't be the only attempted form of mitigation of course, although they're almost universally viewed as such, and as I stated above, GDP still is largely correlated with VMT, meaning driving to stores.











