Correct me if I'm wrong, but I don't think it would be feasible to move all or most cars in the US to use diesel. Diesel, gasoline, and jet fuel are all petroleum distillates that boil off at different temperatures. So each barrel of oil contains so many units of gasoline, so many units of diesel, and so many units of jet fuel/kerosene/mineral oil/whatever.
And I believe that you get much more gasoline out of a barrel of oil than you get diesel, so moving many cars over to diesel would actually increase oil consumption it seems.
And I believe that you get much more gasoline out of a barrel of oil than you get diesel, so moving many cars over to diesel would actually increase oil consumption it seems.