light MERCEDES-BENZ GLC 2020 Repair Manual
[x] Cancel search | Manufacturer: MERCEDES-BENZ, Model Year: 2020, Model line: GLC, Model: MERCEDES-BENZ GLC 2020Pages: 610, PDF Size: 21.19 MB
Page 193 of 610

Fu
nction ofESP ®
trailer stabil izatio n &
WARNIN GRisk ofacci dent inpoo rro ad
and weather condition s
In poor road and weather condition s,the
tr ai le rst abiliz ationcan notpr eve ntlurc hing of
th eve hicle/tr ailercombination. Trailer swit h
a high centerof grav ity ma ytip over bef ore
ES P®
de tects this. #
Alw aysadap tyo ur drivin gst yle to suit
th ecur rent road and weather condi‐
tio ns. When
drivin gwit hatrailer ,ES P®
can stabiliz e
yo ur vehicle ifth etrailer begins tosw erve from
side toside:
R ESP ®
traile rst abiliz ationis act ive abo ve
speeds of40 mph(65 km/h).
R Slight swerving isreduced bymeans ofata r‐
ge ted, individual brak eapplication onone
side. R
Intheeve ntofsevere sw erving, theengine
output isalso reduced andallwheels are
br ak ed.
ES P®
tra iler stabiliz ationma ybe impair edor
ma yno tfun ction if:
R The trailer isno tcon nectedcor rectl yor is
no tde tected prope rly by theve hicle. Fu
nction ofEBD (electr onicbrak efo rc edis‐
tr ibut ion) EB
Dis ch aract erize dby thefo llo wing:
R Mon itor ing and regulating thebr ak epr essur e
on there ar wheels .
R Improve ddr iving stabilit ywhen brakin g,
espe ciallyon ben ds. Fu
nction ofSTEER CONT ROL ST
EER CONTR OLhelpsyo uby trans mitting a
no tice ablesteer ing forc eto thesteer ing wheel in
th edir ect ion requ ired forve hicle stabiliz ation. This
steer ing recomme ndation isgiv en particu‐
lar lyin thefo llo wing situat ions:
R Both right wheels orboth leftwheels areon
a we tor slip pe ry road sur face whe nyo u
br ak e
R The vehicle star ts to skid
Sy stem limit s
ST EER CONTR OLmaybe impa ired orma yno t
fu nctio nin thefo llo wing situat ions:
R ESP®
is deact ivat ed.
R ESP®
is malfun ctionin g.
R The steer ing ismalfunct ioning.
If ES P®
is malfunct ioning,youwill beassis ted
fur ther by theelectr icpo we rst eer ing. Fu
nction ofActiv eBr ak eAs sist Ac
tiveBr ak eAssi stconsi stsof thefo llo wing
func tions:
R Distance warning func tion
R Autonomo usbraki ng func tion Dr
iving and parking 19
1
Page 194 of 610

R
Situ ation-de pendentbraki ng assis tance
R Vehicl eswith Drivin gAss istanc ePa ck‐
ag e:Evasi ve Steer ing Assis tand corner ing
func tion
Ac tiveBr ak eAssi stcan helpyo uto minimize the
ri sk ofacollision withve hicles, cyclis tsor
pedes trians, orreduce theef fects ofsuch acol li‐
sion .
If Ac tiveBr ak eAssi sthas detected arisk ofcolli‐
sion, awa rning tone sou nds and theL dis‐
ta nce warning lam plight sup intheins trument
clus ter.
If yo udo notre act tothewa rning, autono mous
br akin gcan beinit iated incritic alsituat ions.
In espec iallycritic alsituat ions,Ac tiveBr ak e
Assi stcan initia te aut onomo usbrakin gdir ect ly.
In this case, thewa rning lam pand warning tone
occu rsi mu ltane ously with thebr aking applica‐
tion .
If yo uappl yth ebr ak eyo urself inacr itical situa‐
tio nor appl yth ebr ak edur ing autonomous brak‐
ing, situation -dependen tbr aking assistance occu
rs.The brak epr ess ureincr eases uptomax‐
imum full-sto pbr aking ifnec essar y. If
aut onomous braking orsitua tion-dependent
br aking assistanc ehas occurred, displa y1
appear sin themultifunc tiondispla yand then
aut omaticall ygoes outafte ra shor ttime.
If th eaut onomous braking function orthesitua‐
tion -dependen tbr aking assistance istrig ge red,
additional preve ntiv emea suresfo roccupa nt
pr otect ion (PRE-S AFE®
)ma yalso beinitiat ed. &
WARNIN GRisk ofan acci dent caused by
limit eddetection perform anc eof Active
Br ak eAssi st
Ac tiveBr ak eAssi stcanno tal wa ys cle arly
ident ifyobje ctsand complextraf fic situ a‐
tions .
In such case s,Ac tiveBr ak eAssi stmight :
R Giveawa rning orbrak ewit hout reason
R Notgiv eawa rning ornotbr ak e #
Alw ayspa ycar eful attention tothetra f‐
fi c situ ation; donotre ly on ActiveBr ak e
Assi stalon e.Ac tiveBr ak eAssi stisonl y
an aid. Thedriver isresponsible for
maint ainingasui table distance tothe
ve hicle infront, vehicle speed andfor
br aking ingood time. #
Beprepar edtobrak eor sw erve ifnec ‐
essar y. %
Ifth esy stem isuna vailable, the00D4 displa y
appear sin themultifunc tiondispla y.
Als oob ser vethesy stem limits ofActiveBr ak e
Assi st. 19
2
Driving and parking
Page 195 of 610

The
indiv idua lsub func tions areav ailab lein
th efo llo wing speed rang es:
The distance warning func tion issues awa rning
in thefo llo wing situat ions:
R From appr oximat ely4 mp h(7 km/h), ifyo ur
ve hicle iscritically closetoave hicle or pedes
trian, youwill hear anintermit tent
wa rning tone and theL distance warning
lam plight sup intheins trument cluster. Br
ak eimme diat ely ortake evasiv eact ion,pr ov i‐
ded itis saf eto do soand thetraf fic situ ation
al lo ws this.
Th edis tance warning funct ioncan aidyouin thefo llo wing situations withan intermit tent wa rning tone and awa rning lam p: Ve
hicl es
tr av eling in
fr ont St
ation ary
ve hicl es Cr
oss ing
ve hicl es Mo
ving
pedes trians St
ation ary
pedes trians Cr
oss ing
cy cli sts Cy
clis tstrave l‐
ing infront St
ation ary
cy cli sts
Ve hicles
wit hout Driv‐
ing Assis‐
ta nce Pack‐
ag e Up
toappr ox.
15 5mp h
(250 km/h) Up
toappr ox.
50 mph
(80 km/ h) No
react ion Uptoappr ox.
50 mph
(80 km/ h) No
react ion Uptoappr ox.
37 mph
(60 km/ h) Up
toappr ox.
50 mph
(80 km/ h) No
react ion
Ve hicles with
Dr iving Assis‐
ta nce Pack‐
ag e Up
toappr ox.
15 5mp h
(250 km/h) Up
toappr ox.
62 mph
(1 00 km/ h) Up
toappr ox.
43 mph
(70 km/ h) Up
toappr ox.
50 mph
(80 km/ h) Up
toappr ox.
43 mph
(70 km/ h) Up
toappr ox.
43 mph
(70 km/ h) Up
toappr ox.
50 mph
(80 km/ h) Up
toappr ox.
43 mph
(70 km/ h) Dr
iving andparking19
3
Page 198 of 610

R
Activati on byan abr uptst eer ing movement
dur ing asw erving maneu ver.
R Assi stanc edur ing swervin gand stra ight enin g
of theve hicle.
R React ion from aspee dof appr oximat ely
12 mp h(20 km/h) uptoaspee dof appr ox‐
imat ely43 mph(70 km/h).
Yo ucan preve nttheassis tance atanytime by
act ivel yst eer ing.
Cor nering function (onlyve hicl eswith Driv‐
ing Assistanc ePa ckag e)
If adang erofcoll ision from anoncoming vehicle
is de tected whe ntur ning across anoncomi ng
la ne, autonomo usbraki ng can beinitia tedat
speeds below9mp h(1 5 km/h) beforeyo uha ve
lef tth elane inwhic hyo uar edr ivin g. &
WARNIN GRisk ofan acci dent despite
Ev asive St eer ing Assis t
Ev asiv eSt eer ing Assis tcann otalw aysclear ly
ident ifyobje ctsand complextraf fic situ a‐
tions . In
addition, thesteer ing suppor tof Evasiv e
St eer ing Assis tis ge ner ally no tsu fficien tto
av oid acollision.
In suc hcases Evasiv eSt eer ing Assis tcan:
R givean unnec essarywa rning orprov ide
assis tance
R notgi ve awa rning ornotpr ov ide assis‐
ta nce #
Alw ayspa ycar eful attention tothetra f‐
fi c situ ation; donotre ly on Evasiv e
St eer ing Assis talone. #
Beready tobrak eand take evasiv e
act ion ifnec essar y. #
Preve nttheassis tance byact ivel y
st eer ing innon -critical driving situa‐
tion s. #
Drive at an appr opriatespeed ifpedes‐
tr ians areclose tothepat hof your vehi‐
cle. Sy
stem limit s
Fu llsy stem perform anc eis no tav ailable fora
fe w sec ond saf te rswi tching ontheignition or
af te rdr iving off.
The system maybe impair edorma yno tfunc tion
in thefo llo wing situat ions:
R Insno w,rain, fog, hea vyspr ay,if th er eis
gl ar e, indir ect sunlight oringrea tly varying
ambien tlight .
R Ifth esensor sar edir ty,fo gg ed up, damag ed
or covered.
R Ifth esensor sar eim pair eddue tointerfer‐
ence from other radar sour ces, e.g.stro ng
ra dar reflect ions inpar king garage s.
R Ifaloss oftirepr essur eor afa ulty tirehas
been detected and displ aye d.
R IfDS Ris activ ated.
R Incom plextra ffic situat ionswher eobje cts
can notalw aysbe clear lyident ified.
R Ifpedes trians orvehicles movequickl yint o
th esensor detection rang e.
R Ifpe destrians arehidde nby other objects . 19
6
Driving and parking
Page 200 of 610

1
Cruise contro lis selec ted
2 Spee dis save d, cruise control isdeactiv ated
3 Speed issave d, cruise control isactiv ated
% The segmen tsbetween thestor ed speed and
th eend ofthesegment displaylight upin
th espeedome ter.
Sy stem limit s
Cr uise control ma ybe unable tomaint ainthe
st or ed speed onuphill gradients. Thestor ed
speed isresumed whenthegr adient evensout.
Ch ang eint oalowe rge ar ingood timeon long
and steep downhill gradients. Take par ticular
no te ofthis when drivin galaden vehicle. By doing
so,youwill mak euse oftheengine' sbr ak‐
ing effect. Thisre lie vesth eload onthebr ak e
sy stem and preve nts thebr ak es from overheat‐
ing and wearing tooqu ickl y.
Do notus ecr uise contr olinthefo llo wing situa‐
tion s:
R Intraf fic situ ations whichrequ ire freq uent
ch ang esofspee d,e.g .in hea vytraf fic, on
wi nding roads.
R Onslippe ryroads. Accel erati ng can cause
th edr ive wheels tolose tract ion and the
ve hicle could then skid.
R Ifyo uar edr ivin gwhen visibilit yis poor .
Ope ratin gcr uis eco ntr ol &
WARNIN GRisk ofacci dent dueto stor ed
speed
If yo ucall upthestor ed speed andthis is
lo we rth an your cur rent spe ed,th eve hicle
deceler ates. #
Take intoacc ount thetra ffic situat ion
bef orecallin gup thestor ed speed. Re
quirement s:
R ESP®
mus tbe act ivat ed, but notint erve ning .
R The driven spe edisat leas t15 mp h
(20 km/ h).
R The transmis sionisin positio n005B. #
Toactiv atecr uise contr ol: press rock er
switc h1 up. 19
8
Driving and parking
Page 204 of 610

Sy
stem limit s
The system maybe impair edorma yno tfunc tion
in thefo llo wing situat ions:
R Insno w,rain, fog, hea vyspr ay,if th er eis
gl ar e, indir ect sunlight oringrea tly varying
ambien tlight .
R Ifth er eis swir ling dust,e.g. when driving off-
ro ad oron san dysur faces.
R The windsh ield inthear ea ofthecamer ais
dir ty,fo gg ed up, damag edorcovered.
R Ifth era dar sensor sar edir tyor covered.
R Inpar kingga rage sor on roads withsteep
uphill ordownhill gradients.
R Ifth er ear enar row vehicles infront, suchas
bicy cles ormo torcyc les.
In addition ,on slipper yro ads, brakin gor acc el‐
er atin gcan caus eon eor severalwheels tolose
tr act ion and theve hicle could then skid.
Do notuse ActiveDis tance AssistDIS TRONI Cin
th ese situation s. &
WARNIN GRisk ofacci dent from acce ler‐
ati on orbraki ng byActiveDis tance
Assi stDIS TRONI C
Ac tiveDis tance AssistDIS TRONI Cma yacc el‐
er ateor brak ein thefo llo wing cases ,fo r
ex am ple:
R Ifth eve hicle pullsaway usin gAc tiveDis ‐
ta nce AssistDIS TRONI C.
R Ifth estor ed speed iscalled upand is
consider ablyfa ster or slo werth an the
cur rently driven spe ed.
R IfAc tiveDis tance AssistDIS TRONI Cno
lo ng er detects ave hicle infront ordoes
no tre act toreleva nt objects. #
Alw ayscar efully observethetraf fic con‐
di tions andbeready tobrak eat all
times. #
Take intoacc ount thetra ffic situat ion
bef orecallin gup thestor ed speed. &
WARNIN GRisk ofacci dent dueto insuf ‐
fi cie ntdece lera tio nby ActiveDis tance
Assi stDIS TRONI C
Ac tiveDis tance AssistDIS TRONI Cbrak es
yo ur vehicle withup to50% ofthemaximum
possible deceleration.Ifth is decele ratio nis
no tsu fficien t,Ac tiveDis tance Assist
DIS TRONI Caler ts youwit havis ual and
aco ustic warning. #
Inthese cases, adjustyo ur spee dand
ke ep asuf ficie ntdist anc e. #
Brak eth eve hicle yourself and/or take
ev asiv eact ion. &
WARNIN GRisk ofacci dent ifde tection
functi onofActiveDis tance Assist
DIS TRONI Cis impai red
Ac tiveDis tance AssistDIS TRONI Cdo es not
re act orhas alimit edreact ion:
R when drivin gon adif fere nt lane orwh en
ch ang inglane s 202
Drivin gand parking
Page 208 of 610

The
follo wing routeeve nts areta ke nint o
acco unt:
R Bend s
R T-int ersect ions,traf fic cir cle sand tollst a‐
tio ns
R Turnsand exits
R Traf fic jams ahead(only with Liv eTr af fic
( / pag e35 1))
% When theto llst atio nis reac hed, ActiveDis ‐
ta nce AssistDIS TRONI Cad op tsthespeed as
th estor ed speed.
Also, thespeed isreduced ifth etur nsignal indi‐
cat ortochang elane sis swit ched on and one of
th efo llo wing situat ionsisde tected:
R Turning offat intersect ions
R Drivin gon slowing- down lanes
R Drivin gon lanes adjacenttoslo wing-do wn
lanes
The driver isresponsible forch oosing theright
speed andobser vingother road user s.This
applies inpar ticular tointersect ions,traf fic cir‐
cle sand traf fic lights, asroute-based speed adap
tatio ndo es notbr ak eth eve hicle toast and‐
st ill.
When routeguidan ceisact ive, thefirs tsp ee d
ad jus tment iscar ried out automaticall y.Ifth e
tur nsigna lind icatoris swi tched on,theselect ed
ro uteis co nfirmed andfurther speed adjustment
is activ ated.
Speed adjustmentis canc eled inthefo llo wing
cases :
R Ifth etur nsignal indicat orisswitc hedoff
bef oreth ero uteeve nt.
R Ifth edr iver depr esses theacceler ator or
br ak epedal during thepr ocess.
Sy stem limit s
Ro ute-based speedadap tatio ndo es notta ke
ri ght ofwa yre gulations intoaccount .The driver
is responsible forcom plying withro ad traf fic
re gulations anddriving atasuit able speed.
In dif ficul tcondi tions,fo rex am ple unc lear roads,
lane narrowing, wetro ad sur faces, snowor ice ,
or whe ndr ivi ng with atrailer ,th espeed adjust‐
ment made bythesy stem mayno talw aysbe
suit able. Inthese situation sth edr iver mus t
int erve ne acco rding ly. &
WARNIN GRisk ofacci dent inspi teof
ro ute-based speedadj ustm ent
Ro ute-based speedadj ustm entmigh tmal‐
fun ction orbe temp orarily una vailable inthe
fo llo wing situat ions:
R Ifmap datais no tup todat eor available
R Ifyo udo notfo llo wtheselect edroute
guidan ce
R Ifth ese tro uteis re-pl anne d
R Inroad con stru ction area s
R Whe nto wing atrailer
R Inbad weather orroad con dition s
R Ifth eacceler ator pedal isdepr essed #
Adjus tth espeed tothetraf fic situ ation. Se
tting rout e-base dspee dadap tation Re
quirement s:
R ActiveDis tance AssistDIS TRONI Cis acti va‐
te d. 206
Driving andparking
Page 210 of 610

R
The driver presses ast eer ing wheel buttonor
oper ates Touc hCon trol.
If Ac tiveSt eer ing Assis tde tects that asy stem
limit hasbeen reac hed, avisual warning is
issued andawa rning tone sou nds.
Ac tiveSt eer ing Assis tis onl yan aid. Thedriver is
re sponsible forth edis tance totheve hicle in
fr ont, forve hicle speed, forbr aking ingood time
and forst ay ing inlane. Beforech ang inglane s,
th edr iver mus tmak esur eth at theneighbor ing
lane isfree (glance over theshoulder).
Sy stem limit s
Ac tiveSt eer ing Assis thas alimit edsteer ing tor‐
qu efo rlat eral gui dance. Insome cases, the
st eer ing interve ntio nis no tsu fficien tto keep the
ve hicle inthelane ortodrive th ro ugh exits.
The system maybe impair edorma yno tfunc tion
in thefo llo wing instances:
R The reispoor visibilit y,e.g. due tosno w,rain,
fo g, hea vyspr ay,gr ea tly varying ambien t
light orstro ng sha dows onthero adw ay.
R Ther eis glar e, e.g .fr om oncom ingtraf fic,
di re ct sunli ght orreflect ions. R
Insuf ficie ntroad illumin ation.
R The wind shieldisdir ty,fo gg ed up, damag ed
or coveredin thevicinit yof thecamer a,e.g.
by ast icke r.
R No, orseveral,unc lear lane markingsare
pr esen tfo rone lane, orthemar king sch ang e
qu ickl y, e.g. inacon stru ction area orinter‐
secti ons.
R The lane mar kings arewo rnaw ay,dar kor
co veredup, e.g. bydirtor sno w.
R The distance totheve hicle infront istoo
small andthelane markings thus can notbe
de tected.
R The road isnar row and windin g.
R Ther ear eobs tacle son thelane orprojec ting
out intoth elane, suchas objec tmar kers.
The system does notpr ov ide assis tance inthe
fo llo wing condition s:
R Ontigh tbends andwhen turnin g.
R When crossin gint ersect ions.
R Attraf fic cir cle sor tollst atio ns.
R When towing atrailer . R
When activel ych ang inglane without switch‐
ing onthetur nsignal indicat or.
R When thetir epr essur eis toolow.
Dep endingontheselect edvehicle settin gs,
Ac tiveSt eer ing Assis tma ybe una vailable.
Obser vethest atus displa yof ActiveSt eer ing
Assis tin themultifunc tiondispla y
(/ page21 1). &
WARNIN GRisk ofacci dent ifAc tive
St eer ing Assis tune xpect edlystops func‐
tionin g
If th esy stem limits ofActiveSt eer ing Assis t
ar ere ac hed ther eis no guar anteethat the
sy stem will remain activeor wil lke ep the
ve hicle inlane. #
Alw ayske ep your han dson thesteer ing
wheel andobser vethetra ffic car efull y. #
Alw aysst eer theve hicle paying atten‐
tion totraf fic condi tions. 208
Driving and parking
Page 212 of 610

If
th eassis tance grap hicis sho wnwhen chang ‐
ing lane s,thelane chang edispla yappear swit h
an addit ionalarrow point ingtowa rdsth eadja‐
cent lane(/page21 1).
If alan ech ang eis no tposs ible, thear ro w fades
out afte ra fe w sec ond sand ane wlane chang e
mus tbe init iated. Animm ediat elane chang eis
on lypossible onfree wa ysec tion swit hout speed
limi ts.
If th esy stem isim pair ed,ActiveLa ne Chang e
Assi stma ybe canceled .If it is canceled ,th e
Lane Change Cancel edmessag eappe arsin the
multifu nctiondisplay and awa rning tone sou nds. &
WARNIN GRisk ofacci dent from chang ‐
ing lane toan occ upied adjacentlane
Lan eChan geAssi stcanno tal wa ys detect
cle arly ifth eadjacen tlane isfree.
The lane chang emigh tbe init iated although
th eadjacen tlane isno 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. &
WARNIN GRisk ofacci dent ifLane
Ch ang eAssi stune xpectedl yst ops func‐
tionin g
If th esy stem limit ations forLane Change
Assis tha ve been reac hed, ther eis no guar‐
ant eethat thesy stem will remain active.
Lane ChangeAssis tcanno tth en assis tyo u
by appl ying steer ing torq ues . #
Alw aysmonit orthelane chang eand
ke ep your han dson thesteer ing wheel.
Obser vethetra ffic con dition sand steer
and/or brak eif neces sary. Sy
stem limit s
The system limit ations ofActiveSt eer ing Assis t
apply toActiveLa ne Chang eAssi st
( / pag e20 7). The
system mayalso beimpair edorma yno t
func tion inthefo llo wing situat ions:
R The sensorsin there ar bum peraredir ty,
damag edorcoveredby ast icke ror ice and
sno w,forex am ple.
R The exterior lighting ismalfunct ioning.
% The ActiveLa ne Chang eAssi stsensor s
adjus taut omaticall ywhile acer tain dis tance
is be ing driven afte rth eve hicle hasbeen
deliv ered. ActiveLa ne Chang eAssi stis
una vailable oronl ypar tiall yav ailable during
th is teac h-in per iod, noarrow appear sne xt
to theØ ActiveSt eer ing Assis tsymbol
when thetur nsignal indicat orisactiv ated.
Ac tiv atin g/deac tivatin gAc tiv eLan eCha nge
As sist
Multimedia system:
4 © 5
Set ting s5
Assist ance
5 Act ive Lane Change Assist #
Activateor deacti vate thefunc tion.
Fu nction ofActiv eEme rgency Stop Assis t
If th edr iver con tinuall yignor esthevisual or
acous ticwarning toput their hands onthesteer‐ 21
0
Driving and parking
Page 213 of 610

ing
wheel, theBeginn ingEmer gencySt op mes‐
sag eappear sin themultifunc tiondispla y.Ifth e
dr iver still does notre spond, ActiveDis tance
Assi stDIS TRONI Creduces thespeed. Thevehi‐
cle isdeceler ated instag es toast ands till.
De pen dingon thecount ry,at speeds below
40 mph(60 km/h) thehazar dwa rning light s
switc hon aut omat ically.
When theve hicle isstatio nary,thefo llo wing
act ions arecar ried out :
R theve hicle issecur edwithth eelectr icpar k‐
ing brak e
R ActiveDis tance AssistDIS TRONI Cis end ed
R theve hicle isunloc ked
R ifpossible ,an emer gency callis place dto
th eMer cedes- Benzemergency callcent er
The driver can cance lth edeceler ationatany
time byper form ing one ofthefo llo wing actions :
R steer ing
R braking oracceler ating
R pressing ast eer ing-wheel button
R oper ating Touc hCon trol R
activatin gor deac tivatin gAc tiveDis tance
Assi stDIS TRONI C Ov
erview ofActiv eDi stance Assist
DI ST RO NIC displa ysintheins trum ent clus‐
te r The
assis tance grap hicand thest atus displa y
sho wthest atus ofthefo llo wing functionsin the
ins trumen tclus ter:
R ActiveDis tance AssistDIS TRONI C
R Route-based speedadap tatio n
R ActiveSt eer ing Assis t Assis
tantdispla y 1
Route-based speedadap tatio n:typ eof route
eve nt
2 Vehicle infront
3 Distance indicator
4 Setspe cified dist anc e
5 ActiveLa ne Chang eAssi stlane chang edis‐
pla y Dr
ivin gand parking 21
1