One thing I haven't seen anyone note is that once any element of the economy (commuter, company, whatever) converts away from petroleum for transport fuel, they are individually immune to further price increases or supply squeezes.

1) A switch from gas/diesel to natural gas. Well, hopefully it's obvious how one isn't immune to price increases in this case. For the record, it's a limited resource, it's peaked in North America and it's price is also increasing.

2) Any liquid/fuel cell fuel source. How well does it scale? Yes you can get waste oil to run your car from a restaurant down the street, but what happens when 5% of the population find out about the great savings? Suddenly the reataurant realizes that waste oil is a resource that s/he can sell for far more. And now you effectively have to buy the bio diesel (or algae oil) from a station. Growing demand, but will supply ramp up quickly enough? Sure, in the long term price should/might go down but when it's just becoming popular there could be wild price adjustments. Sure, some could be down, but some could be up.

3) electrical power. Whether compressed air or a battery is used for the energy storage mechanism, have you looked at your electrical bill? I'm getting yearly adjustments to the bill twice yearly for the last two years (better than the quarterly I seem to be getting from the natural gas company). How many new nuclear plants are being built in your area? Does your bill show what percentage of your energy comes from what sources? Odds are you'll see 50% from coal, some from gas, and then some from renewables. Coal will get more expensive to ship, and gas is going up. And without breeder reactors nuclear will also rise. When a lot of people are plugging their cars into the grid, there's going to need to be a lot more electricity produced.

I'm unsure what other categories there are, but one won't be immune from price increases. But hopefully the price increases will be less than the petroleum bound competitors.