I predict that only a tiny fraction of car drivers will begin to use bicycles for transportation. If there is a fuel crisis or some other reason for fuel to become more scarce, such as extremely high prices, the percentage change might be a little higher. The citizens here would rather go to war to get cheaper fuel than to begin riding bicycles.
More people will be fatter than now.
The federal government will do more to appease the car drivers in some way if there is a fuel availability problem.
Electric cars will be a higher percentage of vehicles on the road. Once Tesla and others add more inexpensive electric vehicles the field will expand and there will still be more cars on the road than today.
Auto insurance for aluminum vehicles will be sky high and shift people away from wanting to buy them. It is more costly to repair an aluminum vehicle than a steel one. The Ford F 150 will in time lose sales because of this fact.
It is my wish for more electric cars and alcohol powered cars to replace gasoline powered cars.