you could always use a blend of biodiesel, as there is no road tax on a fuel additive.
say 95% bio to 5% dino diesel.

 

Hmmmm... I would guess if the state wants their tax money they wouldn't accept that scenerio.. My way of thinking an additive is there to help lubricity/lower gelling point etc.., where using bio you are trying to get add gallons of fuel at no pump (retail) cost (assuming home made)..

Also, unless you have your percentages swapped, how could 95% Bio be an 'additive'??

Mechanos - good point on the fuel vs road tax, most ppl tend to generalize and consider them one in the same..