2022 MERCEDES-BENZ CLA Owners Manual

R
The wind shield isdir ty,fo gg ed up, dam aged or
co veredin thevicinity ofthecamer a,e.g. bya
sti cker.
R No, orseveral,unclear lanemarkings arepr es-
ent forone lane, orthemar kings chang e
qu ickl y, forex am ple, inacons tructi onarea or
int ersecti ons.
R The lane marking sar ewo rnawa y,dar kor cov-
er ed up, e.g. bydirtor sno w.
R Ifth edist ance totheve hicle infront istoo
shor tand thus thelane markings canno tbe
de tected.
R The roadis na rrow and wind ing.
R Ther ear eobs tacles onthelane orprojecting
out intoth elane, suchas object markers.
The system doesno tpr ov ide assist anceinthefo l-
lo wing conditions:
R Ontight curvesand when turnin g.
R When crossin gint ersecti ons.
R Atroundabouts ortollst ations.
R When thetir epr essur eis toolow. &
W W
ARNI NG ARNI
NGRisk ofaccid ent ifAc tiveSt eer -
ing Assist unexpect edlyst ops function ing
If th esy stem limits ofActiveSt eer ing Assist
ar ere ac hed ther eis no guar anteethat the
sy stem will remain activeor will keep theve hi-
cle inlane . #
Alwayske ep your hands onthesteer ing
wheel andobser vethetra1c carefull y. #
Alwaysst eer theve hicle paying attent ion
to tra1 cco nd itio ns . &
W W
ARNI NG ARNI
NGRisk ofaccid ent ifAc tiveSt eer -
ing Assist unexpect edlyint erve nes
The detection oflane marking sand obje cts
ma ymalfu nctionand cause unexpect edsteer -
ing interve ntions . #
Steer accor dingtotra1 cco nd itio ns . AA
ct iv ct
ivat ing/ deact iv at
ing/ deact ivat ing A at
ing Act iv ct
ive St e
St eer eer
ing Assist ing
Assist
R R
eq eq
uir uir
ements: ements:
R ESP ®
is activ ated, but isno tint erve ning. R
ActiveDist ance AssistDIS TRONI Cis acti va-
te d.
Multimedi asy stem:
4 © 5
Settings 5
Quick Access #
Select 004FSteering Assist. FF
unction ofA unction
ofActiv ctiv
eEmer g e
Emer gency St ency
Stop Assist op
Assist If
th esy stem detects that thedr iver has not
st eer edtheve hicle fora consider ableperiod of
time orhas remo vedth eir hands from thesteer ing
wheel, display1 appear sin theInstr ument Dis-
pla y.Ifth edr iver still does notst eer theve hicle,
or giv es no con/r mation tothesy stem, awa rning Dr
iving andparking
175 175

to
ne sou nds inadd itionto thevisual warning mes-
sag e.
If th edr iver still does notre spond tothewa rning,
th eBeginning Emergency Stopmessag eappear s
in theInstr ument Display.Ifth edr iver still does
no tre spond ,Ac tiveDist ance AssistDIS TRONI C
re duces thespeed. Thevehicle isdecel erated in
st ag es toast ands till.
Depen dingon thecountr y,at speeds below
40 mph(6 0km /h)th ehazar dwa rning lights
switc hon automaticall y.
When theve hicle isstation ary, thefo llo wing
actions arecar ried out:
R The vehicle issecur edwithth eelectr icpar k-
ing brak e.
R ActiveDist ance AssistDIS TRONI Cis ended.
R The vehicle isunl ocked.
R Ifpossible, anemer gency callis pla ced tothe
Mercede s-Benzemergency callcent er.
The driver can cancel thedeceler ationatanytime
by per form ing one ofthefo llo wing actions:
R Steer ing R
Braking oracceler ating
R Deactiv atingActiveDist ance Assist
DIS TRONI C AA
ctiv ctiv
eLane Chang e
Lane ChangeAssi st e
Assi st FF
unctio nof A unctio
nof Activ ctiv
eLane Chang e
Lane ChangeAssi st e
Assi st
Ac tiveLane ChangeAssi stsupp orts thedr iver
when chang inglane sby appl ying steer ing torq ue
if th edr iver activ ates atur nsignal indicat or.
Obser vetheno teson drivi ng systems andyour
re sponsi bility;yo uma yot her wise failto recogn ize
dang ers(/ page157) .
Assis tance when chang inglane sis prov ided ifall
th efo llo wing conditions areme t:
R Youar edr iving onafree wa yor road withmul-
tip lelane sin thedir ection oftrav el.
R The neighbor inglane issepar ated byabr ok en
lane marking .
R Novehicle isde tected intheadjacent lane.
R The vehicle speed isbe tween 50mph
(80 km/h )and 110 mph(1 80 km/h). R
ActiveLane ChangeAssi stisswi tched onin
th emultimedia system.
R ActiveSt eer ing Assist isactiv ated and activ e.
If no vehicle isde tected intheadjacent laneanda
lane chang eis per mitt ed,thelane chang ebeg ins
aTer thedr iver has activ ated thetur nsignal indi-
cat or.This issho wntothedr iver wit hagr een
ar ro w ne xt to the± steer ing wheel symbol.
The Lane Change tothe Left messag e,forex am-
ple, also appear s.IfAc tiveLane ChangeAssi st
has been activatedwit hth etur nsignal indicat or
but alane chang eis no timmed iatelypossibl e,a
gr ay arro w appear sne xt to the± steer ing
wheel symbol, whichre mains green.
When lanechang eassis tance star ts, thetur nsig-
nal indicat orisaut omaticall yactiv ated along with
th edispla yin theInstr ument Display.
If th eassist ancegraphic issho wnwhen chang ing
lane s,an addit ionalarro w appear sin itpoin ting
to wa rdsth eadjacent lane(/page167).
If alane chang eis no tpossibl e,thear ro w isfaded
out aTer afew secon dsand ane wlane chang e
mus tbe initiat ed. Animmed iatelane chang eis 176176
Dr
iving and parking

onl
ypossible onfree wa ysect ionswit hout speed
lim its.
If th esy stem isim pair ed,ActiveLane Change
Assi stma ybe canc eled. Ifit is canc eled, the
Lane Change Cancel edmessag eappear sin the
Ins trumen tDispl ay.
In addit ion,a wa rning tone maysou nd, depending
on thesituation. &
W W
ARNIN G ARNIN
GRisk ofaccident whenchang ing
lane toan occupi edadjace ntlane
Lan eChang eAssis tcann otalw aysclear ly
de tect ifth eadjacent laneisfree.
The lane chang emig htbe initiat edalthoug h
th eadjacent laneisno tfr ee. #
Beforech ang inglane s,mak esur eth at
th eneighbor inglane isfree and ther eis
no dang ertoother road user s. #
Mon itor thelane chang e. &
W W
AR NIN G AR
NIN GRisk ofacciden tif Lan eChang e
Assis tune xpect edlyst ops funct ioning
If th esy stem limit ations forLane Chang e
Assist have been reac hed, ther eis no guar an-
te eth at thesy stem will remain active.
Lane Chang eAssis tcanno tth en assist youby
appl ying steer ing torq ue . #
Alwa ys monit orthelane chang eand
ke ep your hands onthesteer ing wheel.
Obser vethetra1c conditions andsteer
and/or brak eif necessar y. Sy
st Sy
stem limits em
limits
The system limitat ions ofActiveSt eer ing Assist
appl yto ActiveLane ChangeAssi st
(/ page173) .
The system mayals obe impair edorma yno tfunc-
tion inthefo llo wing situations:
R The sensor sin there ar bum peraredir ty,dam-
ag ed orcoveredby ast icke ror ice and snow,
fo rex am ple.
R The exterior lightin gsho wsamalf unct ion. %
The ActiveLane ChangeAssi stsens orsadjust
aut oma tically whi leacer tain dist ance isbeing
dr iven aTer theve hicle hasbeen delivered.
Ac tiveLane ChangeAssi stisuna vailable or
onl ypar tiall yav ailabl edur ing this teac h-in
pr ocess; noarro w appear sne xt to theØ
Ac tiveSt eer ing Assist symbol whenthetur n
signal indicat orisactiv ated.
Selecting A Selecting
Activ ctiv
eLane Chang e
Lane Chang eAssist e
Assist
Multimedia system:
4 © 5
Settings 5
Assistance
5 Active LaneChange Assist #
Select thefunction . AA
ctiv ctiv
eBr e
Br ak ak
eAssist e
Assist FF
unction ofA unction
ofActiv ctiv
eBr e
Br ak ak
eAssist e
Assist
Ac tiveBr ak eAssi stcons istsofthefo llo wing func-
tions:
R Dist ance warning function
R Autonomo usbrak ing functi on
R Situa tion-d ependent brak ing assist anc e Dr
iving andparking
177 177

R
V V
ehicles wit ehicles
withDr h
Dr iving Assist iving
Assist anceP ance
Pac k ac
kag ag
e: e:
Eva-
siv eSt eer ing Assist andcorner ing function
Ac tiveBr ak eAssi stcan help youto minimiz eth e
ri sk ofacolli sion withve hicles, cyclis tsor pedes-
tr ians ortoreduce thee.ect sof suc hacollision.
If Ac tiveBr ak eAssi sthas detected arisk ofcolli -
sion ,a wa rning tone sou nds and theL dis-
ta nce warning lamplights upintheinst rument
clust er.
V V
ehicles wit ehicles
withPRE- S h
PRE- SAFE AFE
® ®
: :
dependi ngon thecoun-
tr y, an addit ionalhap ticwarning occur sin the
fo rm ofslight, repeat edtensio ning oftheseat
belt.
If yo udo notre act tothewa rning, autonomous
br aking canbeinitiat edincritical situations.
In especia lly cr itical situations, ActiveBr ak eAssi st
can initiat eaut onomo usbraki ng directl y.In this
case, thewa rning lampand warning tone occ ur
sim ultaneo uslywit hth ebr aking application.
If yo uappl yth ebr ak eyo urself inacr itical situa-
tion orappl yth ebr ak edur ing autonomous brak -
ing, <0054004A0055005600420055004A0050004F000E0045004600510046004F0045
0046004F0055> braking assistance occur
s.The brak epr essur eincr eases uptomaxi-
mum full-sto pbr aking ifnecessar y.
Obser vetheno teson drivi ng systems andyour
re sponsi bility;yo uma yot her wise failto recogn ize
dang ers(/ page157 ). If
aut onomo usbraking orsituat ion-depen dent
br aking assistancehasoccur red, displa y1
appear sin theInstr ument Displayand then aut o-
maticall ygoes outaTer ashor ttime.
If th eaut onomous braking function orthesitua-
tion-dependen tbr aking assistanceistrigg ered,
additional prev entiv emeasur esforoccupant pro-
te ction (PRE-SAFE®
)ma yalso beinitiat ed. &
W W
ARNIN G ARNIN
GRisk ofan accident causedby
limit eddetection perform ance ofActive
Br ak eAssi st
Ac tiveBr ak eAssi stcanno talw aysclear lyiden-
tify objects andcom plextra1c situations.
In suc hcases ,Ac tiveBr ak eAssi stmight :
R Giveawa rning orbrak ewit hout reason
R Notgiv eawa rning ornotbr ak e
Ac tiveBr ak eAssi stisonl yan aid. Thedriver is
re sponsi bleformaint aining asu1cien tly saf e
dist ance totheve hicle infront ,ve hicle speed
and forbr aking ingood time. #
Alwayspa ycar eful att ent ion tothetra1c
situation; donotre ly on ActiveBr ak e
Assi stalone . #
Beprepa redto brak eor swerve ifneces-
sar y. Also
observe thesy stem limits ofActiveBr ak e
Assi st. 178178
Dr
iving andparking

The
indivi dualsub functi onsar The
indivi dualsub functi onsareav e
av ailabl ein v ailabl
ein var ar
i- i-
ous speed r ous
speed rang ang
es: es:
The distance warning function canissue awa rn-
ing inthefo llo wing situations:
R From appr oximat ely4 mp h(7 km /h),ifyo ur
ve hicle iscriticall yclose toave hicle, cyclis tor
pedes trian, youwill hear anintermitt entwarn-
ing tone and theL distance warning lamp
lights upintheinst rument cluster.
V V
ehicles wit ehicles
withPRE- S h
PRE- SAFE AFE
® ®
: :
dependi ngon the
count ry,an addit ionalhap ticwarning occur s
in thefo rm ofslight, repeat edtensio ning of
th eseat belt.
Br ak eimmediat elyor take evasiv eactio n,prov i-
ded itis saf eto do soand thetra1c situation
allo wsthis.
Dist Dist
ance w ance
war ar
ning function (v ning
function (vehicles wit ehicles
without Dr hout
Driv- iv
-
ing Assist ing
Assist anceP ance
Pac k ac
kag ag
e) e)
The distance warning function canaidyouin the
fo llo wing situations withan intermitt entwarning
to ne and awa rning lamp:
R atspeeds uptoappr oximat ely155 mph
(2 50 km/h) whenapproaching vehicles ahead R
atspeeds uptoappr oximat ely50 mph
(80 km/h )when approaching station aryve hi-
cles, movingpedes trians, andcyclis tsahead
R atspeeds uptoappr oximat ely37 mph
(60 km/h )when approachingcr ossin gcy clis ts
Dis t Dis
tance w ance
war ar
ning funct ion (v ni
ng funct ion (vehicl eswit ehicl
eswithDr h
Dr ivin g iv
in g
Assi st Assi
stance P ance
Pac k ac
kag ag
e) e)
The distance warning function canaidyouin the
fo llo wing situations withan intermitt entwarning
to ne and awa rning lamp:
R atspeeds uptoappr oximat ely155 mph
(2 50 km/h) whenapproaching vehicles ahead
R atspeeds uptoappr oximat ely62 mph
(100 km/h )when approaching station ary
ve hicles
R atspeeds uptoappr oximat ely50 mph
(8 0km/h) whenapproaching moving pedes-
tr ians andcyclists ahead
R atspeeds uptoappr oximat ely43 mph
(70 km/h )when approaching station ary
pedes trians, crossing vehicles andstation ary
and crossin gcy clis ts A A
ut ut
onom ousbr onom
ousbraking funct ion (v aking
funct ion (vehicle swit ehicle
swit hout hout
Dr Dr
iving Assis t ivi
ng Assis tance P ance
Pac k ac
kag ag
e) e)
If th eve hicle istrav eling atspeeds aboveappr ox-
imat ely4 mph (7km /h), theaut onomous braking
function mayint erve ne inthefo llo wing situations:
R atspeeds uptoappr oximat ely124 mph
(200 km/h )when approachingve hicles ahead
R atspeeds uptoappr oximat ely50 mph
(80 km/h )when approachingcy clis tsahead
R atspee dsup toappr oximat ely37 mph
(6 0km/h) whenapproaching moving pedes-
tr ians andcrossing cyclists
R atspeeds uptoappr oximat ely31 mph
(50 km/h )when approachingst ati ona ryvehi-
cles
A A
ut ut
onom ousbr onom
ousbraking funct ion (v aking
funct ion (vehicle swit ehicle
swit hDr h
Dr iv- iv
-
ing Assis t ing
Assis tance P ance
Pac k ac
kag ag
e) e)
If th eve hicle istrave ling atspeeds aboveappr ox-
imat ely4 mp h(7 km /h),th eaut onomous braking
function mayint erve ne inthefo llo wing situations:
R atspeeds uptoappr oximat ely155 mph
(250 km/h )when approaching vehicles ahead Dr
iving and parking
179 179

R
atspeeds uptoappr oximat ely62 mph
(100 km/h )when approachingst ati ona ry
ve hicles
R atspeeds uptoappr oximat ely50 mph
(80 km/h )when approaching cyclis tsahead
R atspeeds uptoappr oximat ely43 mph
(70 km/h )when approachingst ati ona ryand
mo vingpedes trians, crossin gve hicles andsta-
tion aryand crossin gcy clis ts
Si tuat ion-dep endent br Si
tuat ion-dep endent braking assist aking
assistance (v ance
(vehicle s ehicle
s
wit wit
hout Dr hout
Driving Assis t ivi
ng Assis tance P ance
Pac k ac
kag ag
e) e)
The situation -dependent braking assistance can
int erve ne from aspe edofapp roximat ely4 mp h
(7 km/h )in thefo llo wing situations:
R atspeeds uptoappr oximat ely155 mph
(250 km/h )when approachingve hicles ahead
R atspeeds uptoappr oximat ely50 mph
(80 km/h )when approachingst ati ona ryvehi-
cles andvehicles ahead
R atspeeds uptoappr oximat ely37 mph
(60 km/h )when approaching movingpedes-
tr ians andcrossing cyclis ts Si
tuat ion-dep ende ntbr Si
tuat ion-dep ende ntbraking assist aking
assistance (v ance
(vehicle s ehicle
s
wit wit
hDr h
Dr iving Assis t ivi
ng Assis tance P ance
Pac k ac
kag ag
e) e)
The situation -depende ntbraking assistance can
int erve ne from aspe edofapp roximat ely4 mp h
(7 km/h )in thefo llo wing situations:
R atspeeds uptoappr oximat ely155 mph
(250 km/h )when approachingve hicles ahead
R atspeeds uptoappr oximat ely62 mph
(100 km/h )when approachingst ati ona ry
ve hicles
R atspeeds uptoappr oximat ely50 mph
(80 km/h )when approachingcy clis tsahead
R atspee dsup toappr oximat ely37 mph
(60 km/h )when approaching station aryand
mo vingpedes trians, crossing vehicles, and
st ation aryand crossin gcy clis ts
Cance lingabr Cance
lingabr ak ak
eappli catio nof A e
appli catio nof Activ ctiv
eBr e
Br ak e ak
e
Assis t Assis
t
Yo ucan cancel abr ak eapplica tionofActive
Br ak eAssi stat anytime by:
R shar plydepr essin gth eacceler ator pedal or
wit hkic kdo wn
R releasing thebr ak epedal Ac
tiveBr ak eAssi stma ycanc elthebr ak eapplica-
tion when oneofthefo llo wing conditions isful/l-
led:
R Youmaneuv ertoavo idtheobst acle
R Ther eis no long erarisk ofcolli sion
R Anobs tacle isno long erdetected infront of
yo ur vehicle
Ev Ev
asiv asiv
eSt e
St eer eer
ing Assist (onl ing
Assist (onlyv y
vehicles wit ehicles
withDr h
Dr iving iving
Assist Assist
anceP ance
Pac k ac
kag ag
e) e)
Ev asiv eSt eer ing Assist hasthefo llo wing charac-
te risti cs:
R Theab ilit y to detect station aryor mo ving
pedes trians.
R Assis tance thro ugh powe r-assis tedsteer ing if
it de tects asw ervin gmaneu ver.
R Activation byan abr uptst eer ing movement
dur ing asw ervin gmaneuv er.
R Assis tance during swerving andstraigh tening
of theve hicle.
R Reactio nfrom aspeed ofappr oximat ely
12 mph(20 km/h) uptoaspeed ofappr ox-
imat ely43 mph (70km/h). 180180
Dr
iving andparking

Yo
ucan prev ent theassist anceatanytime by
activ elyst eer ing.
Cor Cor
ner ner
ing funct ion (onl ing
funct ion (onl yv y
vehicle swit ehicle
swit hDr h
Dr iving ivi
ng
Assis t Assis
tance P ance
Pac k ac
kag ag
e) e)
If th esy stem detects arisk ofacolli sion withan
oncom ingvehicle when turnin gacr oss anonco m-
ing lane ,aut onom ousbraking canbeinitiat edat
speeds below9mp h(1 5km /h)be fore youha ve
leT thelane inwhic hyo uar edr iving. &
W W
ARNIN G ARNIN
GRisk ofaccident despiteEv a-
siv eSt eer ing Assist
Ev asiv eSt eer ing Assist cannotalw aysre cog-
niz eobje ctsorcom plextra1c situat ions
clear ly.
Mor eover,th esteer ing suppor tpr ov ided by
Ev asiv eSt eer ing Assist isno tsu1cien tto
avo idacollision. #
Alwayspa ycar eful att ent ion tothetra1c
situation; donotre ly on Evasiv eSt eer ing
Assist alone. #
Beprepar edtobrak eor swerve ifneces-
sar y. #
End thesuppor tby activ elyst eer ing in
non -critical situ atio ns. #
Drive at an appr opriatespeed ifth er e
ar epedestr iansclose tothepat hof your
ve hicle. Sy
st Sy
stem limits em
limits
Fu llsy stem perform ance isno tye tav ailabl efo ra
few secon dsaTer switchingontheve hicle oraTer
dr ivi ng o..
If Ac tiveBr ak eAssi stisim pair edorinoper ative
due toamalf unct ion,th e00C7 warning lamp
appear sin theInstr ument Display.
The system maybe impai redor ma yno tfun ction,
par ticular lyin thefo llo wing situations:
R Insno w,rain, fog, hea vyspr ay,if th er eis glar e,
in dir ect sunlight oringreatl yva rying ambient
light.
R Ifth esensor sar edir ty,fo gg ed up, dam aged or
co vered.
R Ifth esensor sar eim pair eddue tointerfere nce
fr om other radar sour ces, e.g.strong radar
re 0ectio nsinapar kingga rage . R
Ifaloss oftirepr essur eor amalf unctionin g
tir ehas been detected and displa yed.
R Incom plextra1c situations whereobjects
canno talw aysbe clear lyident i/ed.
R Ifpedestr iansorvehicles movequickl yint o
th esensor detection rang e.
R Ifped estr ians arehid den byother objects.
R Ifth etypical outline ofapedestr iancanno tbe
distin guished from thebac kgroun d.
R Ifapedestr ianisno tde tected assuc h,e.g .
due tospecial clothing orother objects.
R Ifth edr iver's seat beltisno tfa stene d.
R Oncurves withatight radius.
% The ActiveBr ak eAssi stsens orsadjust auto-
mati callywhile acer tain dist ance isbeing
dr iven aTer theve hicle hasbeen delivered.
Ac tiveBr ak eAssi stisuna vailable oronl ypar -
tiall yav ailabl edur ing thete ac h-in process.
A A
ctiv ctiv
atin g/deact iv atin
g/deact ivatin gA atin
gActiv ctiv
eBr e
Br ak ak
eAssis t e
Assis t
R R
eq eq
uir uir
emen ts: emen
ts:
R The vehicle isswitc hedon. Dr
iving and parking
181 181

Multim
ediasystem:
4 © 5
Set tings 5
Ass istan ce
5 ActiveBrak eAss ist #
Selec tth edesir edsetting .
The setting isretained when thedr ive sy stem
is ne xt star ted.
Deactiv Deactiv
atingA ating
Activ ctiv
eBr e
Br ak ak
eAssist e
Assist
% Itis recommen dedthat youalw ayslea ve
Ac tiveBr ak eAssi stacti vated. #
Select Off.
The distance warning function, theaut ono-
mous braking function andEvasiv eSt eer ing
Assist aredeactiv ated.
When theve hicle isne xt star ted, themiddle
se tting isaut omaticall yselect ed.
% IfAc tiveBr ak eAssi stisdeac tivated, the00D4
symbol appearsin thestatus baroftheInstr u-
ment Displa y. TT
r r
a1c a1c
Sign Assis t Si
gn Assis t FF
unct ionof unct
ionofTr Tr
a1c a1c
Sign Assis t Si
gn Assis t
Tr a1c Sign Assis tde tects tra1c signswit hth e
multif unctioncamer a(/ page157) .It assists
yo uby displa yingdetected speed limitsand over-
ta king restr iction sin theInstr ument Display.
Obser vetheno teson drivi ng systems andyour
re sponsi bility;yo uma yot her wise failto recogn ize
dang ers(/ page157) .
Sin ceTra1c Sign Assis talso uses thedat astor ed
in thena vig ation system, itcan updat eth edispla y
in thefo llo wing situations without detectin gtra1c
sign s.
The camer aalso detects tra1c signswit ha
re str iction indicat ed byan addit ionalsign (e.g.
when wet).Thes ear eonl ydisp laye difare str ic-
ti on appliesor ifth esy stem canno tclear lyde ter-
mine whether there str iction applies.
W W
ar ar
nin gwh en t nin
gwh en the maximu mper he
maximu mpermi ssible spee dis mi
ssible spee dis
ex ex
ceeded ceeded
The system can warnyouifyo uunint entionall y
ex ceed themaximum permissible speed.Todo
th is, youcan specify inthemultimedia system by
ho wmuc hth emaximum permissible speedcan be
exceeded beforeawa rning isissued. Youcan
specify whether thewa rning isto be justa visual
wa rning oran acoustic oneaswell.
Displa Displa
yin t y
in the Ins he
Instr tr
ument Display ument
Display Instr
ument Displayin theWi descr eenCockpit
1 Maximum permissible speed
2 Maximum permissible speedwhenther eis a
re str iction
3 Additional signwithre str iction 18
2 18
2 Dr
iving andpa rking