BMW 5 Series: Remove attached parts 
following use - Saving fuel - Driving tips - BMW 5 Series Owners ManualsBMW 5 Series: Remove attached parts following use

Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use.

Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption.

    Remove unnecessary cargo
    Additional weight increases fuel consumption. ...

    Close the windows and glass sunroof
    Driving with the glass sunroof and windows open results in increased air resistance and raises fuel consumption. ...

    See also:

    Instrument panel features
    1 — Air Outlet. 5 — Beverage Can Cooler Bin. 9 — Power Outlet. 2 — Side Window Demister Outlet. 6 — Glove Compartment. 10 — Climate Controls. 3 — Instrument Cluster. 7 — Heated Sea ...

    Reporting Safety Defects
    In the US If you believe that your vehicle has a defect which could cause a crash or could cause injury or death, you should immediately inform the National Highway Traffic Safety Administratio ...

    Type Approval of Equipment
    Immobilizer system Keyless entry system ...