
If achange inthe speed limit is detected andActive Distance AssistDISTRONIC is activated,Active Distance AssistDISTRONIC adaptsthisnew speed asthestored speed.
The driven speed is adjusted whenthevehicle islevel withthe traffic sign atthe latest. Inthecase of signs indicating entry into an urban area,the speed is adapted accordingtothe speedpermitted withinthe urban area. The speed limit
display inthe instrument display is always upda‐ted whenthevehicle is level withthe traffic sign.
Ifthere is no speedrestriction on an unlimitedstretch ofroad (e.g. on a freeway),therecom‐mended speed is adopted asthestored speed.The system usesthe speedstored on an unlimi‐tedstretch ofroad astherecommended speed.Ifyou do not alterthestored speed on an unlimi‐tedstretch ofroad,therecommended speed is80mph (130 km/h).
IfActive Distance AssistDISTRONIC has beenput into passivemodebypressingthe accelera‐tor pedal, only speed limits whichare higherthanthe set speed are adopted.
Active Speed Limit Assistis only an aid. Thedriver isresponsibleforkeeping a safe distancetothevehicle in front,forvehicle speed andforbraking in good time. The maximum permissiblespeed also depends onfactors suchastheroadsurface and traffic conditions.
System limitationsTemporary speedrestrictions (e.g.for a certaintime or duetoweather conditions) cannot beproperly detectedbythe system. The maximum
permissible speed applyingfor avehicle with atrailer is not detectedbythe system. Inthese sit‐uationsyou must adjustyour speedyourself.
\nWARNINGRisk of accident duetoActiveSpeed Limit Assistadaptingthevehicle'sspeed
The speed adoptedbyActive Speed LimitAssistmay betoo high or incorrect in someindividual cases, suchas:
RInthewet or infog
RWhentowing a trailer
Ensurethatthe driven speed complieswith trafficregulations.
Adjustthe driving speedtosuit currenttraffic andweather conditions.
Function ofroute-based speed adaptation
Thefollowing function is country-dependentand onlyavailable in conjunction withtheDriving AssistancePackage.
Driving and parking181

When Distance AssistDISTRONIC is active,thefunction adjuststhe speed depending ontherouteevents ahead. Depending onthe drive pro‐gram selected,thevehicle negotiatestherouteevent ahead in a fuel-saving, comfortable ordynamic manner. Whentherouteevent has beenpassed,thevehicle accelerates againtothestored speed. The set distancetothevehicle infront,vehicles detected ahead and speedrestric‐tions ahead aretaken into account.
Route-based speed adjustment canbyconfig‐ured inthe multimedia system (→page183).
Routeevents ahead are:
RBends
RT-intersections, traffic circles andtollsta‐tions
RTurns andexits
RTraffic jams ahead (only withLiveTraffic(→page 287))
Whenthetollstation isreached,Active Dis‐tance AssistDISTRONIC adoptsthe speed asthestored speed.
Also,the speed isreduced ifthe turn signaltochange lanes is switched on and one ofthefol‐lowing situations is detected:
RTurning off at intersections
RDriving on slowing-down lanes
RDriving on lanes adjacenttoslowing-downlanes
The driver isresponsibleforchoosingtherightspeed and observingotherroad users. Thisapplies in particulartointersections, traffic cir‐cles and traffic lights, asroute-based speedadaptation does not brakethevehicletoastand‐still.
Whenroute guidance is active,thefirst speedadjustment is carried out automatically.Iftheturn signal indicator is switched on,the selectedroute is confirmed and further speed adjustmentis activated.
Speed adjustment is canceled inthefollowingcases:
RIfthe turn signal indicator is switched offbeforetherouteevent.
RIfthe driver depressesthe accelerator orbrake pedal duringthe process.
System limitationsRoute-based speed adaptation does nottakeright ofwayregulations into account. The driverisresponsiblefor complying withroad trafficregulations and driving at a suitable speed.
In difficult conditions (e.g. unclearroads, narrowlanes,wetroad surfaces, snow or ice) or whendriving witha trailer,the speed adjustment madebythe system may not always be suitable. Inthese situationsthe driver must interveneaccordingly.
\nWARNINGRisk of accident in spiteofroute-based speed adjustment
Route-based speed adjustment might mal‐function or betemporarily unavailable inthefollowing situations:
RIf map data is not uptodate oravailable
RIfyou do notfollowthe selectedrouteguidance
18 2Driving and parking

Ifthe driver does notsteerthevehicleover along period, or has nottaken hold ofthesteeringwheel, arepeatedwarningtone sounds in addi‐tiontothe visualwarning message (dependingonthe country).
Thewarning message does not appear or disap‐pears if one ofthefollowing conditions are met:
RThe driversteersthevehicle.
RThe driver presses asteering wheel button oroperatesTouch Control.
ActiveSteering Assist is only an aid. The driver isresponsibleforthe distancetothevehicle infront,forvehicle speed,for braking in good timeandforstaying in lane. Beforechanging lanes,the driver must make surethatthe neighboringlane is free (glanceoverthe shoulder).
System limitationsActiveSteering Assist has a limitedsteeringtor‐quefor lateral guidance. In some cases,thesteering intervention is not sufficienttokeepthevehicle inthe lane ortodrive pastexits.
The system may be impaired or may not functioninthefollowing instances:
RIn snow,rain,fog, heavy spray, ifthere isglare, direct sunlight,greatlyvarying ambientlight,reflections orstrong shadowsontheroadway.
RInsufficientroad illumination.
RThe windshield inthe area ofthe camera isdirty,fogged up, damaged or covered.
RAbsence of lane markings, or several unclearlane markings, or ifthe markingschangerap‐idly.
RThe distancetothevehicle in front istoosmall andthe lane markingsthus cannot bedetected.
RTheroad is narrow and winding.
RObstacles onthe lane or projecting out intothe lane.
The system does not provide assistance inthefollowing conditions:
ROn tight bends, intersections,tollstations,traffic circles and when turning.
RWhen activelychanging lane without switch‐ing onthe turn signal.
RWhenthe tire pressure istoo low.
\nWARNINGRisk of accident ifActiveSteering Assist unexpectedlystops func‐tioning
Ifthe system limitations ofActiveSteeringAssist arereachedthere is no guaranteethatthe system willremain active or willkeepthevehicle in lane.
Alwayskeepyour hands onthesteeringwheel and observethe traffic carefully.
Alwayssteerthevehicle paying atten‐tiontotraffic conditions.
\nWARNINGRisk of accident ifActiveSteering Assist unexpectedly intervenes
A malfunction inthe detection of lane mark‐ings and objects can occur.
This could cause unexpectedsteering inter‐vention.
184Driving and parking