I believe that as already stated in this thread that diesel, kerosene, heating oil, and other petroleum items are all by products of the refining of crude oil into gasoline.

The intersting thing is that through re-refining each time they can get a much greater percentage of gasoline out of each barrell. i.e. if 80% of a barrell of oil is being ultimately refined into gas to keep up with demand. That only leaves less than 20% available for other petroleum products. In short demand is a ***** and the decision has been made to use all necessary resources to keep gas prices flat and they have forgotten about diesel.

http://science.howstuffworks.com/oil-refining4.htm