Volkswagen began running “Diesel’s Not a Dirty Word” commercials some time in 2009. In fact, Volkswagen is the only major consumer car manufacturer that heavily advertised diesel in recent memory. The main selling points behind diesel are…:

• Lower price per gallon
• Lower pollution

Lower pollution argument aside, does the difference in price per gallon really make sense?

We pulled historical data from U.S. Energy Information Administration and compared price of regular gasoline to the price of diesel over the last 15 years. Results below:

Source: U.S. Energy Information Administration

Note: Price is in cents (eg. 100 cents = $1).

Per graph above, the price of diesel is goes up and down and follows the same trend as regular gas. It is also unclear whether diesel is much cheaper than regular gas since it seems to zig-zag.

Bottom line: think twice before buying into the argument of cost savings with diesel.