认证杯数学中国Word格式文档下载.docx

认证杯数学中国Word格式文档下载.docx

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Predictthetimerequiredtocrossacongestedsection

Abstract

Estimationoftraveltimeisoftenanimportantfeatureinnavigationsoftware.Existingnavigationsoftwaretypicallycapturesreal-timeGPSdatafromtaxisorvehiclesinstalledwiththesoftwaretodeterminecurrentroadconditions.Inaseveretrafficjam,thespeedofthecarisveryslow,sothespeedestimateisveryinaccurate.Asaresult,theestimatedtimeoftrafficcongestionisverypoor.Theactualtimerequiredissometimesseveraltotentimesmorethanthepredictedtime.

Therefore,thedriverreceivesthewrongroadsectioncongestiontimeduringdrivingandchoosesthecongestedroadsectiontopass,thusaggravatingthecongestion,affectingtheurbantrafficpassagerateandpollutingtheurbanenvironment.Inthelongrun,itwillhindertheeconomicandsocialdevelopmentofthecity.Therefore,theestablishmentofanaccuratepredictionmodelforcrowdedroadsections，soastoprovidebasictechnicalsupport,cannarrowthegapbetweentheexpectationandtheactualtraveltimefornavigationsoftware,andthedrivercanchooseareasonabledrivingroadtoappropriatelyreducethesituationoftheseriouslycongestedroadsectionsintherushhourbyacceptingtheaccurateestimationoftraveltime.Therefore,thecontentofthispaperisclosetotherealityoflifeandhaspracticalsignificance.

Keywords:

trafficjamtime,trafficpassrate,predictionmodel

Catalog

Introduction

1.1Researchbackground

Inrecentyears,withtherapidgrowthofChina'

snationaleconomy,Chinahasbecometheworld'

ssecondlargesteconomyandtheworld'

slargestmanufacturingcountry.ThelevelofurbanizationinChinahasbeensignificantlyimprovedandtheprocessofurbanizationhasbeensignificantlyaccelerated.Amongthem,urbantrafficproblemhasbecomeoneofthefocusofsocialconcern.Withthepopularizationofprivatecars,carsarethemainmeansoftransportationforcitizens,andtheurbanroadloadisbecomingincreasinglyserious.Thephenomenonofroadcongestion,trafficchaosandtrafficjamsometimesoccurs,orbecomesnormal.Accordingtothesurvey,80to90percentoftheroadcapacityofChina'

scitieswithmorethanonemillionpeoplehasreacheditslimit.Thecityspeedofmotorvehicleisdroppedfrom30km/hin1960sto13km/h.Worseningenvironmentandtrafficcongestionproblemisincreasinglyprominent.Thelowpassrate,increasedfuelfees,increasedexhaustemissions,thedeteriorationofurbanenvironment,travelwaitingtime,travelcostsandsoon,hasseriouslyaffectedthecitizens'

travelefficiency,travelexperience,andthephysicalandmentalhealth.

Trafficcongestionhasattractedmuchattentionovertheyears.Itisacomplexphenomenoncausedbytheinteractionofvariousfactors.Itisnotonlyatechnicalproblem,butalsoaneconomicandsocialproblem.Duetothedifferentdevelopmentlevelofeachcity,thereasonsfortrafficcongestionarealsodifferent.Generallyspeaking,itisrelatedtourbanlayout,urbanroadplanning,trafficmanagementandurbandevelopmentmanagement.Comparedwiththeurbantrafficproblemsinforeigndevelopedcountries,wecanfindthatthereisabiggapbetweenChinesecitiesandforeigncitiesintermsofdevelopmentmode,layoutplanningandroadsystemconstruction.Citiesathomeandabroadarefacingthesameproblemsuchastheincreasingnumberofprivatecars，streamofrushhour.Foreigncitieswiththeperfectpublictransportationsystem,theeffectivecongestiondredgetechnologymethod,theurbantrafficcongestionproblemismoreoptimisticthanthatinourcountry.Thisisalsotheadvantageintheconstructionandmanagementofurbantransportationsystemthatweshouldlearnfromforeigncities.

Urbantrafficcongestioniscloselyrelatedtosocialdevelopment,economicdevelopment,urbanlayoutplanning,urbantrafficmanagementsystem,etc.However,theabovefactorsneedlong-termdevelopmentandadjustmenttoimprove.Atpresent,wecanonlyalleviatetrafficcongestionfromthetechnicalleveloftrafficcongestiondredging,whichisalsothebackgroundofthispaper.

1.2Thesignificanceofthepaper

Theproblemofurbantrafficcongestionisverycommonallovertheworld.Themethodsofforeigndevelopedcountriestodealwithurbancongestionareworthyofourstudyandreference.Inthelongrun,comparedwithforeigncitieslayoutplanning,urbanmanagementsystem,urbanpublictransportationsystem,urbantrafficmanagementsystem,urbanresidentsqualityandaseriesofadvantages,atthepresentstage,wecannotmakeeffectiveadjustmentstoeasetheproblemofurbantrafficcongestiontomakeprogress.Butwecanimproveonthenavigationtechnology,throughreal-timefeedbackofcarspeed,improvethepredictionaccuracyoftraveltime,toprovideaccurateroadtrafficinformationfordriverstounderstand,makesomejudgment,chooseasuitableroad,soastoalleviatetheserioustrafficjamandimprovetheefficiencyofdriving.Intheshortterm,theimprovementintheaccuracyofthetechnicallevelcanalleviatethetrafficcongestionproblem,whichissuitablefortheactualsituationofChina'

surbandevelopmentatthisstage,withpracticalresearchsignificancefortheapplicationoftheorytopracticeandthesolutionoftheactualtrafficcongestionproblem.

Anoverviewoftrafficcongestion

2.1Thedefinitionoftrafficcongestion

Trafficjamreferstothetrafficphenomenonthatwhenthenumberofvehicles,passingacertainroadexceedsthetotalcapacityoftheroadinacertainperiodoftime,theexcesspartofthevehicleswillstayontheroad.TheMinistryofPublicSecurityofChinadefinesthecongestedintersectionsandthecongestedsectionsrespectively.Congestionintersection:

thephenomenonthatthelengthofvehiclestrandedattheintersectionwithoutsignallightsexceeds250m,orthevehiclecontrolledbysignallightsattheintersection,failstopassafterthreesignalcycles,isdefinedasacongestionintersection.Congestedroadsection:

thevehicleisstuckonthedrivingroadformorethan1km.

Trafficjamismainlyaphenomenonthatthetrafficcapacityprovidedbyroadtrafficfacilitiescannotmeetthecurrenttrafficdemandandcannotbedredgedintime.Trafficcongestioncanbedividedintotwoaspects:

timeandspace.Urbantrafficcongestionoftenappearsinsomespecificmomentsandareas.Insomecases,trafficcongestionisjustaninadequateandinappropriateuseoftrafficresourcesbytraveldemand.Ofcourse,thereisalsotheproblemoftrafficcongestioncausedbysufficientroadareaandunreasonableroadstructure.Therefore,simplyusingthedelaytimeorthelengthofthestrandedlengthtoexpressthetrafficcongestionstatecannotfullyreflecttheessenceofcongestion,norprovideacorrectevaluationindexfortheimprovementofcongestion.Atthesametime,theacceptanceofcongestionvarieswiththesizeofthecity,thelocationofcongestion,thedurationofcongestionandthecrowd.Congestionalsoexistswhenthetotalcapacityoftheroadpermits.Inthiscase,thecongestionisshortandacceptable,whilethecongestionbeyondthetotalcapacityoftheroadislongandunacceptable.Thecongestionproblemthatpeoplewanttosolveismainlythelatter.Therefore,trafficcongestioncanbeclassifiedintotwocategories:

acceptablecongestionandunacceptablecongestion.Congestionismeasuredfromthefollowingperspectives:

（1）Acceptablemaximumtraveltime:

themaximumtraveltimerequiredfortheimplementationoftravelgoals,beyondwhichtrafficcongestionisinevitable.

（2）Acceptabletravelspeed:

themaximumtimerequiredtocrosstheroad,whichrepresentsthedelaystatusinthecurrentstate.

（3）Delayrate:

theabsolutedifferencebetweentheactualtravelrateandtheacceptabletravelrate,whichcanbeusedtoevaluatetrafficcongestion.

（4）Totaldelay:

representsthetotaltimelosscausedbycongestion.

（5）Relativedelayrate:

theratiobetweenthedelayrateandtheacceptabletravelratecanreflectthedelaydegreemoreintuitively.

（6）Accessibility:

theabilitytoachievetravelgoalswithintheacceptablemaximumtraveltime,andtheratiobetweentheactualtraveltimeandtheacceptablemaximumtraveltime.

2.2Thenatureoftrafficcongestion

Duetothecomplexityofurbantrafficcongestion,wemustfirstlymakeadeepanalysisofthecharacteristicsofurbancongestion,inordertounderstandandsummarizetheattributesoftrafficcongestion.

（1）Timeofcongestion:

duetodifferenttimeofoccurrenceofcongestionevents,theimpactonroadcapacityisalsodifferent.Congestionoccursduringthepeakperiod,withthecontinuousincreaseoftrafficflow,itwillcertainlyaggravatethecongestion.Accordingtothesizeoftrafficflow,differentperiodsofcongestioncanbedividedintopeakperiod,flatperiodandtroughperiod.

（2）Geographicallocationofcongestion:

congestionindifferentareaswillhavedifferenteffectsonthecapacityofthewholeroad.Congestiononkeyroadswillquicklycauseseriouscongestionspread,generallydividedintodowntownsection,importantsection,generalsection,secondarysec