How can oil companies deal with the relative supply and demand for petrol and diesel fractions?

The supply and demand for diesel and gasoline (petrol) creates problems for refineries because sometimes the vehicle fleet demand does not match the product distribution produced by the refinery. If diesel demand is much higher than gasoline demand, but gasoline and diesel are produced in relatively equal amounts, then the gasoline will be oversupplied to the market. A refinery can only affect its product distribution slightly and each refinery is built to process a particular type of crude oil. Switching crude oils in a refinery requires complex analysis of Metallurgy, capacity limitations, and profitability.