wheel MERCEDES-BENZ GLS 2017 Workshop Manual

! Do not warm up the engine with the vehicle
stationary. Drive off immediately. Avoid high
engine speeds and driving at full throttle until
the engine has reached its operating temper-
ature.
Only shift the automatic transmission to the
desired drive position when the vehicle is sta-
tionary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery roads.
You could otherwise damage the drive train.
! Mercedes-AMG vehicles: at low engine oil
temperatures below 68 ‡ (+20 †), the max-
imum engine speed is restricted in order to
protect the engine. To protect the engine and
maintain smooth engine operation, avoid driv-
ing at full throttle when the engine is cold.
SmartKey positions
SmartKey
Z
To remove the SmartKeyG
Power supply for some consumers, such as
the windshield wipersH
Ignition (power supply for all consumers)
and drive position
I
To start the engine
i The SmartKey can be turned in the ignition
lock even if it is not the correct SmartKey for
the vehicle. The ignition is not switched on.
The engine cannot be started.
KEYLESS-GO
General notes
Vehicles with KEYLESS-GO are equipped with a
SmartKey featuring an integrated KEYLESS-GO
function and a detachable Start/Stop button. A check which periodically establishes a radio
connection between the vehicle and the Smart-
Key determines whether a valid SmartKey is in
the vehicle. This occurs, for example, when
starting the engine.
When you insert the Start/Stop button into the
ignition lock, the system needs approximately
two seconds recognition time. You can then use
the Start/Stop button.
Pressing the Start/Stop button several times in
succession corresponds to the different key
positions in the ignition lock. This is only the
case if you are not depressing the brake pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts immedi-
ately.
To start the vehicle without actively using the
SmartKey: R
the Start/Stop button must be inserted in the
ignition lock. R
the SmartKey must be in the vehicle. R
the vehicle must not be locked with the
SmartKey or KEYLESS-GO ( Y
page 75).
Do not keep the SmartKey: R
with electronic devices, e.g. a mobile phone
or another SmartKey. R
with metallic objects, e.g. coins or metal foil. R
inside metallic objects, e.g. a metal case.
This can impair the functionality of the KEY-
LESS-GO key.
Do not keep the KEYLESS-GO key in the tem-
perature-controlled cup holder ( Y
page 303).
Otherwise, the KEYLESS-GO key will not be rec-
ognized.
If you lock the vehicle with the SmartKey's
remote control or with KEYLESS-GO, after a
short time: R
you will not be able to switch on the ignition
with the Start/Stop button. R
you will not be able to start the engine with the
Start/Stop button until the vehicle is
unlocked again.
If you lock the vehicle centrally using the button
on the front door ( Y
page 80), you can continue
to start the engine with the Start/Stop button.
The engine can be switched off while the vehicle
is in motion by pressing and holding the Start/
Stop button for three seconds. This function
operates independently of the ECO start/stop
automatic engine switch-off function.138
Driving
Driving and parking

D Neutral
Do not shift the transmission to N
while driving. Otherwise, the auto-
matic transmission could be dam-
aged.
No power is transmitted from the
engine to the drive wheels.
Releasing the brakes will allow you to
move the vehicle freely, e.g. to push
it or tow it.
If ESP ®
is deactivated or faulty: shift
the transmission to position N if the
vehicle is in danger of skidding, e.g.
on icy roads.
If you switch the engine off with the
transmission in position R or D , the
automatic transmission shifts to N
automatically.
! Rolling in neutral N can damage
the drive train.
: Drive
The automatic transmission changes
gear automatically. All forward gears
are available.
Driving tips
Changing gear The automatic transmission shifts to the indi-
vidual gears automatically when it is in trans-
mission position D . This automatic gear shifting
behavior is determined by: R
the selected drive program R
the position of the accelerator pedal R
the road speed
Accelerator pedal position Your style of driving influences how the auto-
matic transmission shifts gear: R
little throttle: early upshifts R
more throttle: late upshifts Kickdown Use kickdown for maximum acceleration. X
Depress the accelerator pedal beyond the
pressure point.
The automatic transmission shifts to a lower
gear depending on the engine speed. X
Ease off the accelerator pedal once the
desired speed is reached.
The automatic transmission shifts back up.
Rocking the vehicle free Shifting the transmission repeatedly between
gears D and R may help to free the vehicle if it
has become stuck in slush or snow. The vehi-
cle's engine management system limits the
speed to a maximum of 5 mph (9 km/h) when
shifting back and forth. To shift back and forth
between transmission positions D and R , move
the DIRECT SELECT lever up and down past the
point of resistance.
Towing a trailer X
Drive in the middle of the engine speed range
on uphill gradients. X
Depending on the uphill or downhill gradient,
use the left-hand steering wheel paddle
shifter ( Y
page 150) to select a lower gear,
even if cruise control or Distance Pilot
DISTRONIC are activated.
Drive programs
Slippery drive program The Slippery drive program has the following
characteristics: R
reduced engine and transmission settings for
optimum propulsion on slippery or snow-cov-
ered roads. R
optimized ESP ®
stability control on slippery or
snow-covered roads. R
the vehicle has improved driving stability on
slippery or snow-covered roads, for example.Automatic transmission 149
Driving an d parking Z

Comfort drive program The Comfort drive program has the following
characteristics: R
comfort-oriented engine and transmission
settings. R
optimal fuel consumption resulting from the
automatic transmission shifting up sooner. R
the vehicle pulling away more gently in
forward and reverse gears, unless the accel-
erator pedal is depressed fully. R
the automatic transmission shifting up
sooner. This results in the vehicle being driven
at lower engine speeds and the wheels being
less likely to spin.
Sport drive program The Sport drive program has the following char-
acteristics: R
sporty engine and transmission settings. R
the automatic transmission shifting up later.
the fuel consumption possibly being higher as
a result of the later automatic transmission
shift points. R
the suspension exhibits sporty damping (vehi-
cles with AIRMATIC).
Drive program Sport Plus (Mercedes-
AMG vehicles) The Sport Plus drive program has the following
characteristics: R
the vehicle exhibits particularly sporty driving
characteristics. R
the vehicle pulling away in first gear. R
the automatic transmission shifting up later.
the fuel consumption possibly being higher as
a result of the later automatic transmission
shift points. R
the suspension exhibits particularly firm
springing and damping settings (vehicles with
AIRMATIC). R
the ECO start/stop function is deactivated, it
can, however, be activated again using the
ECO button ( Y
page 143). Individual drive program In the Individual drive program, the following
properties of the drive program can be selected: R
the drive (engine and transmission manage-
ment) R
the transmission R
the suspension R
all vehicles (except Mercedes-AMG vehicles):
the steering R
all vehicles (except Mercedes-AMG vehicles):
availability of the ECO start/stop function
To select the gears in the Individual drive pro-
gram permanently using the steering wheel pad-
dle shifters, select the permanent manual gear-
shift program.
Information about configuring the Individual
drive program with the multimedia system can
be found in the Digital Operator's Manual.
Manual gear shifting
General notes You can change gear yourself using the steering
wheel paddle shifters. The transmission must be
in position D .
Depending on which steering wheel paddle
shifter is pulled, the automatic transmission
immediately shifts into the next gear down or
up, if permitted.
To use manual shifting, you have two options: R
temporary setting R
permanent setting
If you activate manual gearshifting, the multi-
function display will show the current gear
instead of transmission position D .
If manual gearshifting is deactivated, the gears
will be selected automatically.150
Automatic transmission
Driving and parking

Temporary setting X
To activate: shift the DIRECT SELECT lever to
position D .X
Pull steering wheel paddle shifter C or D .
Temporary setting will be active for a certain
amount of time. Under certain conditions the
minimum amount of time is extended, e.g. in the
case of lateral acceleration, during an overrun
phase or when driving on steep terrain. X
To deactivate: pull steering wheel paddle
shifter D and hold it in place.
or X
Use the DIRECT SELECT lever to switch the
transmission position.
or X
Use the DYNAMIC SELECT controller to
change the drive program.
Permanent setting (all vehicles except
Mercedes-AMG vehicles)
X
To activate: shift the DIRECT SELECT lever to
position D .X
Press button C . X
To deactivate: press button C .
or X
Use the DYNAMIC SELECT controller to
change the drive program.
Permanent setting (Mercedes-AMG
vehicles) X
To activate: shift the DIRECT SELECT lever to
position D . X
Press button C .
Indicator lamp D lights up.X
To deactivate: press button C .
or X
Use the DYNAMIC SELECT controller to
switch to the Individual drive program.
Indicator lamp D goes out.
Shifting gears
! Mercedes-AMG vehicles: the automatic
transmission does not shift up automatically
even when the engine limiting speed for the
current gear is reached. When the engine lim-
iting speed is reached, the fuel supply is cut to
prevent the engine from overrevving. Always
make sure that the engine speed does not
reach the red area of the tachometer. There is
otherwise a risk of engine damage.Automatic transmission 151
Driving an d parking Z

X
To shift up: pull steering wheel paddle
shifter D .
The automatic transmission shifts up to the
next gear.
All vehicles (except Mercedes-AMG vehi-
cles): if the maximum engine speed on the
currently engaged gear is reached and you
continue to accelerate, the automatic trans-
mission automatically shifts up in order to
prevent engine damage. X
To shift down: pull steering wheel paddle
shifter C .
The automatic transmission shifts down to
the next gear.
Automatic down shifting occurs when coast-
ing.
If the engine exceeds the maximum engine
speed when shifting down, the automatic
transmission protects against engine damage
by not shifting down.
Shift recommendation
The gearshift recommendations assist you in
adopting an economical driving style. The rec-
ommended gear is shown in the multifunction
display. X
Shift to recommended gear D according to
gearshift recommendation C when shown in the multifunction display of the instrument
cluster.
Upshifting (Mercedes-AMG vehicles)
! The automatic transmission does not shift
up automatically even when the engine limit-
ing speed for the current gear is reached.
When the engine limiting speed is reached,
the fuel supply is cut to prevent the engine
from overrevving. Always make sure that the
engine speed does not reach the red area of
the tachometer. There is otherwise a risk of
engine damage.
C
Gear indicator D
Upshift indicator
Before the engine speed reaches the red area,
an upshift indicator will be shown in the multi-
function display. X
When the UP message appears in the multi-
function display, pull on the right-hand steer-
ing wheel paddle shifter.
Kickdown Mercedes-AMG vehicles: kickdown is only
possible in the temporary setting. X
For maximum acceleration, depress the
accelerator pedal beyond the pressure point.
The automatic transmission shifts to a lower
gear depending on the engine speed. X
Shift back up once the desired speed is
reached.
During kickdown, you cannot shift gears using
the steering wheel paddle shifters.
If you apply full throttle, the automatic trans-
mission shifts up to the next gear when the
maximum engine speed is reached. This pre-
vents the engine from overrevving.152
Automatic transmission
Driving an d parking

Problems with the transmission Problem
Possible causes/consequences and P Solutions
The transmission has
problems shifting gear. The transmission is losing oil. X
Have the transmission checked at a qualified specialist workshop
immediately.
7G-TRONIC:
The acceleration ability
is deteriorating.
The transmission no lon-
ger changes gear. The transmission is in emergency mode.
It is only possible to shift into second gear and reverse gear.X
Stop the vehicle. X
Shift the transmission to position P .X
Switch off the engine. X
Wait at least ten seconds before restarting the engine. X
Shift the transmission to position D or R .
If D is selected, the transmission shifts into second gear; if R is
selected, the transmission shifts into reverse gear. X
Have the transmission checked at a qualified specialist workshop
immediately.
9G-TRONIC:
The acceleration ability
is deteriorating.
The transmission no lon-
ger changes gear. The transmission is in emergency mode.
It is only partly possible to engage the gears or the transmission is in
position N . X
Stop the vehicle. X
Shift the transmission to position P .X
Switch off the engine. X
Wait at least ten seconds before restarting the engine. X
Shift the transmission to position D or R .X
Have the transmission checked at a qualified specialist workshop
immediately.
Transfer case This section is only valid for vehicles with 4-
wheel drive (4MATIC). Power is always trans-
mitted to both axles.
! Performance tests may only be carried out
on a 2-axle dynamometer. The brake system
or transfer case could otherwise be damaged.
Contact a qualified specialist workshop for a
performance test.
! Because ESP ®
is an automatic system, the
engine and ignition must be switched off
(SmartKey in position 0 or 1 or Start/Stop
button in position 0 or 1 ) when the electric
parking brake is being tested on a brake dyna-
mometer (maximum 10 seconds).
Braking triggered automatically by ESP ®
may
seriously damage the brake system. ! Vehicles with 4MATIC must not be towed
with either the front or the rear axle raised, as
doing so will damage the transmission.
Refueling
Important safety notes
G WARNING
Fuel is highly flammable. If you handle fuel
incorrectly, there is a risk of fire and explo-
sion.
You must avoid fire, open flames, creating
sparks and smoking. Switch off the engine
and, if applicable, the auxiliary heating before
refueling. Refueling 153
Driving and parking Z

overfilling. DEF may leak if overfilled. Mercedes-
Benz offers a special disposable hose with over-
fill protection. You can obtain this from any
authorized Mercedes-Benz Center. DEF is avail-
able in a variety of containers and receptacles.
Only use the disposable hose with the
Mercedes-Benz DEF refill canisters.
DEF refill bottle
! Only screw on the DEF refill bottle hand-
tight. Otherwise, the thread of the DEF refill
bottle could be damaged and DEF could leak
out.
X
Unscrew the protective cap from DEF refill
bottle C .X
Place DEF refill bottle C on the filler neck as
shown and screw it on clockwise until hand-
tight. X
Press DEF refill bottle C towards the filler
neck.
The DEF tank is filled. This may take up to one
minute.
i When DEF refill bottle C is no longer
pressed, filling stops and the bottle may be
taken off again after being only partially emp-
tied. X
Release DEF refill bottle C .X
Turn DEF refill bottle C counter-clockwise
and remove it. X
Screw the protective cap onto DEF refill bot-
tle C again.
DEF refill canisters are available at many gas
stations or at a qualified specialist workshop.
Refill bottles without a threaded cap do not pro-
vide overfill protection. DEF may leak if overfil-
led. Mercedes Benz offers special refill bottles
with a threaded seal. These are available at any
authorized Mercedes-Benz Center. Parking
Important safety notes
G WARNING
Flammable material such as leaves, grass or
twigs may ignite if they come into contact with
hot parts of the exhaust system or exhaust
gas flow. There is a risk of fire.
Park the vehicle so that no flammable mate-
rials come into contact with parts of the vehi-
cle which are hot. Take particular care not to
park on dry grassland or harvested grain
fields.
G WARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example: R
release the parking brake. R
shift the automatic transmission out of the
parking position P . R
start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
! Always secure the vehicle correctly against
rolling away. Otherwise, the vehicle or its driv-
etrain could be damaged.
To ensure that the vehicle is secured against
rolling away unintentionally: R
the electric parking brake must be applied. R
the transmission must be in position P and the
SmartKey must be removed from the ignition
lock. R
the front wheels must be turned towards the
curb on steep uphill or downhill gradients. R
the empty vehicle must be secured at the
front axle with a wheel chock or similar, for
example, on uphill or downhill gradients. R
a laden vehicle must also be secured at the
rear axle with a wheel chock or similar, for
example, on uphill or downhill gradients. Parking 159
Driving and parking Z

This helps you to avoid overheating the
brakes and wearing them out excessively.
When you take advantage of engine braking, a
drive wheel may not turn for some time, e.g.
on a slippery road surface. This could cause
damage to the drive train. This type of damage
is not covered by the Mercedes-Benz war-
ranty.
Do not depress the brake pedal continuously
while the vehicle is in motion, e.g. causing the
brakes to rub by constantly applying light pres-
sure to the pedal. This results in excessive and
premature wear to the brake pads.
Use the left-hand steering wheel paddle shifter
to shift into a lower gear in good time on long
and steep downhill gradients. This is especially
important if the vehicle is laden.
This also applies if you have activated cruise
control, the speed limiter or Distance Pilot
DISTRONIC.
This will use the braking effect of the engine, so
that less braking will be required to maintain the
speed. This relieves the load on the brake sys-
tem and prevents the brakes from overheating
and wearing too quickly.
Heavy and light loads
G WARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This
increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately. Drive
on for a short while. This allows the airflow to
cool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rain
without braking, there may be a delayed reac-
tion from the brakes when braking for the first time. This may also occur after the vehicle has
been washed or driven through deep water.
You then have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehicle
washed, brake firmly while paying attention to
the traffic conditions. This will warm up the
brake discs, thereby drying them more quickly
and protecting them against corrosion.
Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance. R
Brake occasionally to remove any possible
salt residue. Make sure that you do not
endanger other road users when doing so. R
Carefully depress the brake pedal and the
beginning and end of a journey. R
Maintain a greater distance to the vehicle
ahead.
Servicing the brakes
! The brake fluid level may be too low, if: R
if the red brake warning lamp lights up in
the instrument cluster and R
you hear a warning tone while the engine is
running
Observe additional warning messages in the
multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked immediately.
Consult a qualified specialist workshop to
arrange this.
! A function or performance test should only
be carried out on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult a qualified spe-
cialist workshop in advance. You could oth-
erwise damage the drive train or the brake
system.
! Because ESP ®
is an automatic system, the
engine and ignition must be switched off
(SmartKey in position 0 or 1 or Start/Stop
button in position 0 or 1 ) when the electricDriving tips 165
Driving and parking Z

Off-road fording
! Under no circumstances should you accel-
erate before entering the water. The bow
wave could cause water to enter and damage
the engine and other assemblies.
! Do not open any of the vehicle's doors while
fording. Otherwise, water could get into the
vehicle interior and damage the vehicle's
electronics and interior equipment. R
Establish how deep the water is and the char-
acteristics of the body of water before ford-
ing. R
Select the highest possible vehicle level. R
Shift to a lower gear using the left-hand steer-
ing wheel paddle shifter. R
Avoid high engine speeds. R
Enter and exit the water at a flat place and at
a steady walking pace. R
Drive slowly and at an even speed through the
water. R
Ensure that a bow wave does not form as you
drive. R
Do not stop and do not switch off the engine.
Water offers a high degree of resistance, and
the ground is slippery and in some cases
unstable. Therefore, it is difficult and danger-
ous to pull away in the water. R
Clean any mud from the tire tread after ford-
ing. R
Apply the brakes to dry them after fording.
Always observe the fording depth values
( Y
page 385).
Winter driving
G WARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
G DANGER
If the exhaust pipe is blocked or adequate
ventilation is not possible, poisonous gases such as carbon monoxide (CO) may enter the
vehicle. This is the case, e.g. if the vehicle
becomes trapped in snow. There is a risk of
fatal injury.
If you leave the engine or the auxiliary heating
running, make sure the exhaust pipe and area
around the vehicle are clear of snow. To
ensure an adequate supply of fresh air, open a
window on the side of the vehicle that is not
facing into the wind.
Have your vehicle winter-proofed at a qualified
specialist workshop at the onset of winter.
Drive particularly carefully on slippery road sur-
faces. Avoid sudden acceleration, steering and
braking maneuvers. Do not use cruise control or
Distance Pilot DISTRONIC.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed: X
Shift the transmission to position N .
When driving in snow with or without snow
chains, select driving program Slippery
( Y
page 145).
i Vehicles with a diesel engine: do not
cover the radiator, e.g. with a protective
cover. The measuring function of the on-
board diagnosis system may otherwise pro-
vide inaccurate values. Some of these values
are required by law and must therefore always
be accurate.
The outside temperature indicator is not
designed to serve as an ice-warning device and
is therefore unsuitable for that purpose.
Changes in the outside temperature are dis-
played after a short delay.
Indicated temperatures just above the freezing
point do not guarantee that the road surface is
free of ice. The road may still be icy, especially in
wooded areas or on bridges. You should pay
special attention to road conditions when tem-
peratures are around the freezing point.
For more information on driving with snow
chains, see ( Y
page 348).
For more information on driving with summer
tires, see ( Y
page 348).
Observe the notes in the "Changing a wheel"
section ( Y
page 366).Driving tips 167
Driving and parking Z

Off-road driving
Important safety notes
G WARNING
If you drive on a steep incline at an angle or
turn when driving on an incline, the vehicle
could slip sideways, tip and rollover. There is a
risk of an accident.
Always drive on a steep incline in the line of
fall (straight up or down) and do not turn the
vehicle.
G WARNING
Flammable material such as leaves, grass or
twigs may ignite if they come into contact with
hot parts of the exhaust system. There is a risk
of fire.
When driving off road or on unpaved roads,
check the vehicle's underside regularly. In
particular, remove parts of plants or other
flammable materials which have become
trapped. In the case of damage, contact a
qualified specialist workshop.
G WARNING
If the vehicle level is high, the vehicle center of
gravity is raised. This could cause the vehicle
to tip over more easily on uphill or downhill
gradients. There is a risk of an accident.
Select the lowest possible vehicle level.
! There is a risk of damage to the vehicle if: R
the vehicle becomes stuck, e.g. on a high
curb or an unpaved road R
you drive too fast over an obstacle, e.g. a
curb, speed bumps or a pothole in the road R
a heavy object strikes the underbody or
parts of the chassis
In situations like this, the body, the under-
body, chassis parts, wheels or tires could be
damaged without the damage being visible.
Components damaged in this way can unex-
pectedly fail or, in the case of an accident, no
longer withstand the strain they are designed
to.
If the underbody paneling is damaged, com-
bustible materials such as leaves, grass or twigs can gather between the underbody and
the underbody paneling. If these materials
come in contact with hot parts of the exhaust
system, they can catch fire.
In such situations, have the vehicle checked
and repaired immediately at a qualified spe-
cialist workshop. If on continuing your jour-
ney you notice that driving safety is impaired,
pull over and stop the vehicle immediately,
paying attention to road and traffic condi-
tions. In such cases, consult a qualified spe-
cialist workshop.
When driving off-road, substances such as sand,
mud and water or water mixed with oil may get
into the brakes. This could result in a reduced
braking effect or in total brake failure and also in
increased wear and tear. The braking charac-
teristics change depending on the material
ingressing the brakes. Clean the brakes after
driving off-road. If you detect a reduced braking
effect or grinding noises, have the brake system
checked in a qualified specialist workshop as
soon as possible. Adapt your driving style to the
different braking characteristics.
Driving off-road increases the likelihood of dam-
age to the vehicle, which, in turn, can lead to
failure of the mechanical assembly or syst ems.
A
dapt your driving style to suit the terrain con-
ditions. Drive carefully. Have damage to the
vehicle rectified immediately at a qualified spe-
cialist workshop.
Do not switch to transmission position N when
driving off-road. If you try to brake the vehicle
using the service brake, you could lose control
of the vehicle. If the gradient is too steep for your
vehicle, drive back down in reverse gear.
General notes Read this section carefully before driving your
vehicle off-road. Practice by driving over more
gentle off-road terrain first.
Familiarize yourself with the characteristics of
your vehicle and the gear shift operation before
driving through difficult terrain.
The following driving systems are specially
adapted to off-road driving: R
the Offroad drive program (vehicles without
Off-Road Engineering package)
( Y
page 217) R
Offroad and Offroad Plus drive programs
(vehicles with Off-Road Engineering package)
( Y
page 218)168
Driving tips
Driving and parking