Original sentence: It is sometimes claimed that diesel engine cars or minicars also get good mileage, or even consume less fuel than the Prius.Prius advocates reply that some of these claims are false or exaggerated, and that while some other cars may have a slight advantage in miles per gallon of fuel, this does not take into account other disadvantages of diesel such as pollution, fuel availability, and maintenance; that diesel fuel is more carbon-dense than gasoline so that comparison by volume (e.gallons or liters) favors diesel more than comparison by fuel weight or by carbon dioxide emissions; that the amount of currently wasted used vegetable oil available for conversion into biodiesel is limited; while minicars are far smaller and less suited to applications where more passenger or cargo space is needed or where a very small car may be less safe