Isn't the first step Reduce? Any reduction in petroleum usage is good, removal of urban emissions is better. Diesel trucks operate mostly on the motorway and

Isn't the first step Reduce? Any reduction in petroleum usage is good, removal of urban emissions is better. Diesel trucks operate mostly on the motorway and they can get a good speed there, creating more efficiency. (unlike American big rigs, Euro-trucks are smaller and more efficient, from what I recall.) Cars meanwhile drive locally, pollute where you breathe, and with stat/stop traffic are not efficient consumers of fuel.