DES MOINES, IA – The Des Moines Police Department has purchased 23 new patrol cars, four of which are six-cylinder models that will use less fuel, according to the Des Moines Register.

The other 19 are traditional eight-cylinder Ford Crown Victorias.

The smaller Dodge Chargers and Chevrolet Impalas are expected to get about 17 miles per gallon in the city, while the Crown Victorias average about 12 mpg, according to the Register.

Officers plan to assess the mileage and savings, durability and performance and then decide if they want to buy more of the smaller-engine vehicles for patrol work, Capt. Doug Harvey said. Two Toyota Prius models joined the unmarked fleet, which for nearly three years has included eight Honda Accord hybrids, reported the Register.

The police department spent $800,000 on gasoline last year, according to the Register. A total of 4.1 million miles were driven by department employees.