Diesel fuel simply packs more energy in every gallon that Gas fuel which makes it more economical overall. Diesel engine are still more efficient than Gas engine, but less so far those who are mostly engaged in city driving, Diesel fuel and Gas fuel cost about the same.

Diesel fuel is thicker than gasoline and as such provide more power and milage per gallon, Gasoline engine on the other hand are lighter and deliver higher performance than diesel engine... Conversely Gasoline powered cars and easier and less expensive to maintain and fuel efficiency is constantly improving.

WHY DIESEL ENGINE ARE BETTER THAN GASOLINE???

diesel fuel is thicker than gasoline, which means it evaporates slower, Diesel fuel also has more energy density. These futures are another reason why diesel engine tend to have Better fuel economy than Gas engine.