There are several other variables that can affect fuel economy with on-highway applications. Road congestion, inadequate tire pressure, poor axle and front end alignment, vertical-rib and/or open-top trailers can have an adverse affect on fuel economy. Even small, seemingly inconsequential additions of bug deflectors or leaving the side windows open can also cost money.

Most fuel economy complaints can be explained with a basic understanding of some of the variables that affect fuel efficiency. These complaints typically occur during the winter months when fuel economy drops significantly. Customers purchasing new trucks during the winter months will experience this phenomenon. Not only do they suffer the fuel economy loses of the winter months but also have new tires and a minimum 30,000-mile "break-in" period to contend with. All new vehicle components (engine, transmission, drive axle, drive line U-joints, wheel bearings) require a "wear-in" period.