brake VOLVO XC90 TWIN ENGINE 2020 Service Manual

DRIVER SUPPORT
328
City Safety braking for oncoming vehicles (p. 336)
Automatic braking during delayed evasivemaneuvers with City Safety (p. 335)
City Safety in crossing traffic (p. 333)
City Safety steering assistance for evasivemaneuver (p. 335)
City Safety limitations (p. 337)
City Safety messages (p. 340)
City Safety sub-functions
City Safety 56
can help the driver avoid a colli-
sion with a vehicle, cyclist or large animal ahead by reducing the vehicle's speed usingits automatic braking function.
If the difference in speed is greater than the speeds specified below, the City Safety auto-brake function cannot prevent a collision, butit can help mitigate its effects.
Vehicles
City Safety can help prevent a collision with a vehicle ahead by reducing your vehicle's speedby up to 60 km/h (37 mph).
Cyclists
City Safety can help prevent a collision with a cyclist ahead by reducing your vehicle's speedby up to 50 km/h (30 mph).
Pedestrians
City Safety can help prevent a collision with a pedestrian ahead by reducing your vehicle'sspeed by up to 45 km/h (28 mph).
Large animals
If there is a risk of colliding with a large ani- mal, City Safety can help reduce your vehicle'sspeed by up to 15 km/h (9 mph). The braking function for large animals is pri- marily intended to mitigate the force of a colli-sion at higher speeds. Braking is most effec- tive at speeds above 70 km/h (43 mph) andless effective at lower speeds.
City Safety sub-functions
Function overview.
Acoustic collision warning signal
Collision warning symbol
Camera/radar sensor distance monitoring
City Safety carries out three steps in the fol- lowing order:
1. Collision warning
2. Brake assistance
3. Auto-brake Descriptions of what happens in these three steps are provided below.
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1 - Collision warning
The driver is first alerted to the risk of an immi- nent collision. In vehicles equipped with a head-up display *,
a flashing warning symbol will be displayed on the windshield.
Collision warning symbol on the windshield.
NOTE
Visual warnings on the windshield may be difficult to notice in cases of strong sun-light, reflections, extreme light contrasts,or if the driver is wearing sunglasses or isnot looking straight ahead.
City Safety can detect pedestrians, cyclists or vehicles that are stationary, are moving in thesame direction as your vehicle and are aheadof your vehicle. City Safety can also detect pedestrians, cyclists or large animals that arecrossing the road in front of your vehicle. If there is a risk of a collision with a pedestrian, large animal, cyclist or another vehicle, thedriver will be alerted with light, sound and pul-sations in the brake pedal. At lower speeds,during hard braking or if the accelerator pedalis pressed, the brake pedal pulsation warningwill not be given. The intensity of the brakepedal pulsations varies according to the vehi-cle's speed.
2 - Brake assistance
If the risk of a collision increases after the colli- sion warning, brake support will be activated. If the system determines that the pressure the driver is exerting on the brake pedal is insuffi-cient to prevent the collision, brake supportwill increase pressure.
3 - Auto-brake
The automatic braking function is activated at the last moment. If the driver has not taken evasive action by this stage and a collision is imminent, theautomatic braking function will be triggered.This occurs whether or not the driver is press-ing the brake pedal. Full braking force will beapplied to reduce the speed at impact orreduced braking effect will be applied if this issufficient to avoid the collision.
The seat belt tensioner may be activated whenthe automatic braking function is triggered. In certain situations, auto-braking may begin with a limited braking force before applyingfull braking force. If City Safety has prevented a collision, the vehicle will be kept at a standstill until thedriver takes action. If the vehicle has slowed toavoid colliding with a slower-moving vehicleahead, your speed will be reduced to that vehi-cle's speed. Auto-braking can always be cancelled if the driver presses hard on the accelerator pedal.
NOTE
When City Safety activates the brakes, the brake lights come on.
When City Safety applies the brakes, a text message will appear in the instrument panelto notify the driver that the function is/wasactivated.
WARNING
City Safety may not be used to change how the driver operates the vehicle. Thedriver must not only rely on City Safety tobrake the vehicle.

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Related information
City Safety
™ (p. 327)
City Safety in crossing traffic (p. 333)
City Safety braking for oncoming vehicles (p. 336)
City Safety limitations (p. 337)
Head-up display
* (p. 145)
Seat belt tensioners (p. 52)
Setting a warning distance for City Safety
City Safety 57
is always active, but the func-
tion's warning distance can be adjusted.
NOTE
The City Safety function cannot be deacti- vated. It is activated automatically eachtime the engine/electric motor is started.
The alert distance determines the sensitivity of the system and regulates the distance atwhich the light, sound and brake pulsationswill be activated. To select warning distance:
1. Select
SettingsMy CarIntelliSafein the center display's Top view.
2. Under
City Safety Warning, tap Late,Normal or Early to set the desired warn-
ing distance.
If the driver feels that the
Early setting is giv-
ing too many warnings or finds them irritating, the
Normal or Late warning distance settings
can be selected instead. If the driver feels that the warnings are too fre- quent and distracting, the warning distancecan be reduced. This will reduce the total number of warnings, but it will also result inCity Safety providing warnings at a later stage. The
Late warning distance setting should
therefore only be used in exceptional cases, such as when a more dynamic driving style ispreferred.
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WARNING
No automatic system can guarantee 100% correct function in all situations.You should therefore never test use ofCity Safety in the direction of people,animals or vehicles – this could lead tosevere damage, serious personal injuryor even death.
City Safety warns the driver if there is arisk of collision, but the function cannotreduce the driver's reaction time.
Even if the warning distance has been set to
Early, warnings may be per-
ceived as late in certain situations – e.g. when there are large speed differ-ences or if the vehicle ahead suddenlybrakes heavily.
With the warning distance set to
Early,
warnings come further in advance. This may cause the warnings to come morefrequently than with warning distance
Normal, but is recommended since it
can make City Safety more effective.
NOTE
The warning with direction indicators for Rear Collision Warning * is deactivated if
the collision warning distance in the City Safety function is set to the lowest level "
Late".
The seat belt tensioning and braking func- tions remain active.
Related information
City Safety
™ (p. 327)
City Safety limitations (p. 337)
Rear Collision Warning
* (p. 341)
Detecting obstacles with City Safety
City Safety 58
can help the driver detect other
vehicles, cyclists, large animals and pedes- trians.
VehiclesCity Safety can detect most vehicles that are stationary or are moving in the same directionas your vehicle. In some cases, it can alsodetect oncoming vehicles and crossing traffic. For City Safety to be able to detect a vehicle in the dark, its headlights and taillights must beon and clearly visible.
Cyclists
Examples of what City Safety would interpret to be a cyclist: clear body and bicycle shapes.
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DRIVER SUPPORT
332For good performance, the system's function for cyclist detection needs the clearest possi-ble information about the contours of the bicy-cle and of the cyclist's head, arm, shoulders,legs, torso and lower body in combinationwith normal human movements. If large portions of the cyclist's body or the bicycle itself are not visible to the function'scamera, it will not be able to detect a cyclist. The system can only detect adult cyclists rid- ing on bicycles intended for adults.
WARNING
City Safety is supplementary driver sup- port, but it cannot detect all cyclists in allsituations and, for example, cannot see:
partially obscured cyclists.
cyclists if the background contrast of the cyclist is poor - warning and brakeinterventions may then be late or notoccur at all.
cyclists in clothing that hides theirbody contour.
bikes loaded with large objects.
The driver is always responsible for ensur- ing that the vehicle is driven correctly andwith a safety distance suitable for thespeed.
Pedestrians
Examples of what the system considers to be a pedestrian: clear body contours.
For good performance, the system's function for pedestrian detection needs the clearestpossible information about the contours of thepedestrian's head, arm, shoulders, legs, torsoand lower body in combination with normalhuman movements. In order to detect a pedestrian, there must be a contrast to the background, which coulddepend on clothing, weather conditions, etc. Ifthere is little contrast, the person may bedetected late or not at all, which may result ina delayed reaction from the system or no reac-tion at all. City Safety can detect pedestrians even in dark conditions if they are illuminated by thevehicle's headlights.
WARNING
City Safety is supplementary driver sup- port, but it cannot detect all pedestrians inall situations and, for example, cannot see:
partially obscured pedestrians, people in clothing that hides their body con-tour or pedestrians shorter than 80 cm(32 in.).
pedestrians if the background contrastof the pedestrians is poor - warningand brake interventions may then belate or not occur at all.
pedestrians who are carrying largeobjects.
The driver is always responsible for ensur- ing that the vehicle is driven correctly andwith a safety distance suitable for thespeed.

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Large animals
Examples of what City Safety would interpret as a large animal: stationary or moving slowly and withclear body contours.
For good performance, the system's function for detecting large animals (e.g. moose,horses, etc.) needs the clearest possible infor-mation about body contours. This entailsbeing able to detect the animal straight fromthe side in combination with normal move-ments for that animal. If parts of the animal's body are not visible to the function's camera, the system will not beable to detect the animal. City Safety can detect large animals even in dark conditions if they are illuminated by thevehicle's headlights.
WARNING
City Safety is supplementary driver sup- port, but it cannot detect all large animalsin all situations and, for example, cannotsee: partially obscured larger animals.
larger animals seen from the front or from behind.
running or fast moving larger animals.
larger animals if the contrast of the ani-mal's background is poor - warningand brake interventions may thenoccur late or not at all.
smaller animals such as cats and dogs.
The driver is always responsible for ensur- ing that the vehicle is driven correctly andwith a safety distance suitable for thespeed.
Related information
City Safety
™ (p. 327)
City Safety limitations (p. 337)
City Safety in crossing traffic City Safety 59
can assist the driver when turn-
ing into the path of an oncoming vehicle in an intersection.
Sector in which City Safety can detect an oncoming vehicle in crossing traffic.
In order for City Safety to detect an oncomingvehicle in situations where there is a risk of acollision, that vehicle must be within the sec-tor in which City Safety can analyze the situa-tion. The following criteria must also be met:
your vehicle's speed must be at least 4 km/h (3 mph)
your vehicle must be making a left turn
the oncoming vehicle's headlights mustbe on
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335
City Safety steering assistance for evasive maneuver City Safety steering assistance can help the driver steer away from a vehicle/obstaclewhen it is not possible to avoid a collision bybraking alone. City Safety steering assistanceis always activated and cannot be switchedoff.
Your vehicle swerves away
Slow-moving/stationary vehicle or obsta- cle.
City Safety helps provide assistance bystrengthening the driver's steering move-ments, but only if the driver has begun evasiveaction and the system detects that the driver'ssteering movements are not sufficient to avoida collision. The brake system is used simultaneously to further strengthen steering movements. The function also helps stabilize the vehicle after ithas passed the obstacle. City Safety steering assistance can detect:
vehicles
cyclists
pedestrians
large animals
Related information

City Safety
™ (p. 327)
City Safety limitations (p. 337)
Automatic braking during delayed evasive maneuvers with CitySafety
City Safety 60
can assist the driver by auto-
matically braking the vehicle when it is not possible to avoid a collision by steering alone.
City Safety assists the driver by periodically attempting to predict possible "escaperoutes" to the sides of the vehicle in the eventa slow-moving or stationary vehicle were to bedetected at a late stage.
Your vehicle (1) cannot detect any potential escape routes for veering away from the vehicle ahead (2)and may therefore apply the brakes at an earlierstage.
Own vehicle
Slow-moving/stationary vehicles

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336City Safety will not intervene to automatically apply the brakes if it is possible for the driverto avoid a collision by steering the vehicle. However, if City Safety determines that an evasive maneuver would not be possible dueto traffic in the adjacent lane(s), the functioncan assist the driver by automatically startingto apply the brakes at an earlier stage.
Related information

City Safety
™ (p. 327)
City Safety limitations (p. 337)
City Safety braking for oncoming vehicles City Safety can help you apply the brakes for an oncoming vehicle in your lane.
If an oncoming vehicle veers into your lane and a collision is unavoidable, City Safety canhelp reduce your vehicle's speed to attempt tomitigate the force of the collision.
Own vehicle
Oncoming vehicles
The following criteria must be met for the function to work:
your vehicle's speed must be above4 km/h (3 mph)
the road must be straight
your lane must have clear side lane mark-ings
your vehicle must be positioned straight inyour lane
the oncoming vehicle must be positionedwithin your vehicle's lane markings
the oncoming vehicle's headlights mustbe on
the function can only handle “front-to-front” collisions
the function can only detect vehicles withfour wheels.
WARNING
Warnings and brake interventions due to an imminent collision with an oncomingvehicle always come very late.
Related information

City Safety
™ (p. 327)
City Safety limitations (p. 337)
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This function is not available on all markets.

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Other limitations
WARNING
The driver support system only issues a warning for obstacles detected by its radarsensor – thus, a warning may come after adelay or not at all. Never wait for a warning or assistance. Apply the brakes when necessary.
WARNING
Warnings and brake interventions can be triggered late or not at all if the traf-fic situation or external influences pre-vent the camera and radar unit fromproperly detecting pedestrians,cyclists, large animals or vehiclesahead of the vehicle.
To be able to detect vehicles at night,its front and rear lights must work andilluminate clearly.
The camera and radar unit have a lim-ited range for pedestrians and cyclists– the system can provide effectivewarnings and brake interventions if therelative speed is lower than 50 km/h(30 mph). For stationary or slow-mov-ing vehicles, warnings and brake inter-ventions are effective at vehicle speedsof up to 70 km/h (43 mph). Speedreduction for large animals is less than15 km/h (9 mph) and can be achievedat vehicle speeds over 70 km/h(43 mph). At lower speeds, the warn-ing and brake intervention for large ani-mals is less effective.
Warnings for stationary or slow-mov-ing vehicles and large animals can bedisengaged due to darkness or poorvisibility.
Warnings and brake interventions for pedestrians and cyclists are disen-gaged at vehicle speeds over 80 km/h(50 mph).
Do not place, affix or mount anythingon the inside or outside of the wind-shield, or in front of or around the cam-era and radar unit – this could disruptcamera-based functions.
Objects, snow, ice or dirt in the area ofthe camera sensor can reduce thefunction, disengage it completely orgive an improper function response.

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WARNING
The City Safety auto-brake function can prevent a collision or reduce colli-sion speed, but to ensure full brakeperformance the driver should alwaysdepress the brake pedal – even whenthe car auto-brakes.
The warning and steering assistanceare only activated if there is a high riskof collision – you must therefore neverwait for the collision warning or CitySafety to intervene.
Warnings and brake interventions forpedestrians and cyclists are disen-gaged at vehicle speeds over 80 km/h(50 mph).
City Safety does not activate auto-braking intervention during heavyacceleration.
NOTE
The function uses the vehicle's camera and radar sensor, which has certain generallimitations.
Market limitationsCity Safety is not available in all countries. If City Safety is not shown in the center display's
Settings menu, your vehicle is not equipped
with this function. In the center display's Top view, tap:
SettingsMy CarIntelliSafe
Related information
City Safety
™ (p. 327)
Camera/radar sensor limitations (p. 322)