See also:

Making adjustments in 5 mph (Canada: 10 km/h) increments
Briefly press the cruise control lever beyond the pressure point, up 1 for a higher speed or down 2 for a lower speed. The last speed stored is increased or reduced. ...

Setting a speed
WARNING   Keep in mind that it may take a brief moment until the vehicle has made the necessary adjustments. Increase or decrease the set vehicle speed to a value that the prevailing ro ...

Vehicle data, GL 450
The data stated here refers specifically to a vehicle with standard equipment. Consult an authorized Mercedes-Benz Center for the data for all vehicle variants and trim levels. ...