Because diesel is commonly used for non-vehicle purposes, diesel fuel is frequently marked with color to indicate if it was taxed at the vehicle rate or not: h

Because diesel is commonly used for non-vehicle purposes, diesel fuel is frequently marked with color to indicate if it was taxed at the vehicle rate or not: https://en.wikipedia.org/wiki/Diesel_fuel#Taxation https://en.wikipedia.org/wiki/Diesel_fuel#Taxation However, if you're talking about a carbon tax instead of a roads maintenance tax, burning diesel or gas is the same, whether it's in a car or not.