See also:

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

Problems with the SmartKey
Problem Possible causes/consequences and Solutions You cannot lock or unlock the vehicle using the SmartKey. The SmartKey battery is discharged or nearly discharged. - ...

Everything considered: integral Mercedes-Benz safety concept
The comprehensive Mercedes approach to integral safety also applies in the new R-Class. This trailblazing safety philosophy goes well beyond compliance with standardised crash test regulations. It ...