Mercedes-Benz 2009 CL-Class Operator's Manual page 364

Controls in detail
Driving systems
The DISTRONIC Plus has not yet detected the
vehicle changing lanes. There will be
insufficient distance to the lane-changing
vehicle.
Narrow vehicles
Because of their narrow profile, the vehicles
traveling near the outer edges of the lane
have not yet been detected by the DISTRONIC
Plus. There will be insufficient distance to the
preceding vehicles.
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Obstacles and stationary vehicles
The DISTRONIC Plus does not brake for
obstacles or stationary vehicles. If, for
example, the vehicle detected in front of you
changes lanes to bypass an obstacle or
stationary vehicle in front of it, the
DISTRONIC Plus will not brake for the
obstacle or stationary vehicle.
Cross-traffic
The DISTRONIC Plus may inadvertently
detect crossing vehicles. If you switch on the
DISTRONIC Plus, for example, at a traffic light
with cross traffic, the vehicle may suddenly
start to drive off.