Which rationing method was instituted for gasoline in the mid-1970s?

I believe the answer is: purchasing days determined by license plate numbers

At that time, the Gasoline reserve was in an extremely high demand while its production was still extremely limited.
To handle this, the government divide the purchasing right based on the end number of license plate. (odd numbers could buy at day X while even numbers could buy it at day Z) 

The best sociological research method would have to be using experiments although it has some disadvantages as well