
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

must be initiated. An immediate lanechange isonly possible on freeway sections without speedlimits.
Ifthe system is impaired,Active Lane ChangeAssistmay be canceled. If it is canceled,theLane Change Canceledmessage appears inthemultifunction display and awarningtone sounds.
\nWARNINGRisk of accident fromchang‐ing lanetoan occupied adjacent lane
Lane ChangeAssistcannot alwaysdetectclearlyifthe adjacent lane is free.
The lanechange might be initiated althoughthe adjacent lane is not free.
Beforechanging lanes, make surethatthe neighboring lane is free andthere isno dangerto otherroad users.
Monitorthe lanechange.
\nWARNINGRisk of accident if LaneChange Assistunexpectedlystops func‐tioning
Ifthe system limitationsfor Lane ChangeAssist havebeenreached,there is no guar‐anteethatthe system willremain active.
Lane Change Assist cannotthen assistyoubyapplyingsteeringtorques.
Always monitorthe lanechange andkeepyour hands onthesteering wheel.Observethe traffic conditions andsteerand/or brake if necessary.
System limitationsThe system limitations ofActiveSteering AssistapplytoActive Lane Change Assist(→page183).
The system may also be impaired or may notfunction inthefollowing situations:
RThe sensors intherear bumper are dirty,damaged or covered,for instanceby asticker or ice and snow.
RTheexterior lighting is malfunctioning.
Activating/deactivatingActive Lane ChangeAssistMultimedia system:
VehiclekAssistance
SelectLane Change Assist.
Activate sor deactivate Sthe function.
Function ofActive EmergencyStop AssistIfthe driver continually ignoresthe visual oracousticwarningtoputtheir hands onthesteer‐ing wheel,theBeginning Emergency Stopmes‐sage appears inthe multifunction display.Ifthedriverstill does notrespond,Active DistanceAssistDISTRONICreducesthe speed. Thevehi‐cle is decelerated instagestoastandstill.Atspeeds below 40mph (60 km/h)the hazardwarning lights switch on automatically.
Whenthevehicle isstationary,thefollowingactions are carried out:
RThevehicle is secured withthe electric park‐ing brake
RActive Distance AssistDISTRONIC is ended
RThevehicle is unlocked
18 6Driving and parking

3Active Distance AssistDISTRONIC active,speedstored, novehicle detected (brightvehicle symbol)
4Active Distance AssistDISTRONIC active,speedstored,vehicle detected (greenvehi‐cle symbol)
5Active Distance AssistDISTRONIC androute-based speed adaptation active, speedstored
On highways or high-speed majorroads,thegreençvehicle symbol is displayed cycli‐cally whenthevehicle isreadytopullaway.
SpeedometerThestored speed is highlighted onthe speedom‐eter. Ifthe speed ofthevehicle in front orthespeed adjustment is lessthanthestored speedduetotherouteevent ahead,the segments inthe speedometer light up.Activation or deactiva‐tion ofActive Distance AssistDISTRONIC, aswell as alterationstothe speed duetomanual orautomatic adoption ofthe speed limit, are dis‐played inthe controlfeedback ofthe multifunc‐tion display on a single line.
ActiveSteering Assiststatus display
1Graysteering wheel:ActiveSteering Assistswitched on and passive
2Greensteering wheel:ActiveSteering Assistswitched on and active
3Flashingsteering wheel: prompttothe drivertoactively confirmor transition from activetopassivestatus, system limitation detected
Duringthe transition fromthe activetopassivestatus, symbol3is shown as enlarged andflashesyellow.Oncethe system is passive, sym‐bol1is shown as grayinthe multifunction dis‐play.
Function of HillStart Assist
HillStart Assist holdsthevehiclefor a shorttime when pullingawayon a hill underthefol‐lowing conditions:
RVehicles with automatic transmission:The transmission is in position [or ^.
RThe electric parking brake isreleased.
This givesyou enough timetomoveyourfootfromthe brake pedaltothe accelerator pedaland depress it beforethevehicle beginstorollaway.
\nWARNINGRisk of accident and injuryduetothevehiclerollingaway
After a short time, HillStart Assist no longerholdsthevehicle and it canrollaway.
Therefore, swiftly moveyourfootfromthe brake pedaltothe acceleratorpedal. Never attempttoleavethevehi‐cle if it is being heldbyHillStart Assist.
18 8Driving and parking