"To get better gas mileage" means using less fuel when driving a vehicle, leading to increased efficiency and longer distances traveled per gallon of gas. Full definition
Also, the car gets good gas mileage for its size. (autolist.com)
I was worried about not getting good gas mileage with an SUV, but the Edge gets just as much gas mileage as my previous vehicle did, which was a sedan. (autolist.com)
It also gets good gas mileage when traveling on the freeway. (autolist.com)