高速公路前置指路标志设置距离及其安全影响_英文_郭唐仪

  • 格式:pdf
  • 大小:1.01 MB
  • 文档页数:6

JournalofSoutheastUniversity(EnglishEdition) Vo.l26,No.4,pp.622-627Dec.2010 ISSN1003)7985Placementdistanceoffreewayexitadvanceguidesignanditssafetyimpacts

GuoTangyi1 DengWei1 HouJiansheng2 LuJohn3(1SchoolofTransportation,SoutheastUniversity,Nanjing210096,China)(2TransportationInstitute,InnerMongoliaUniversity,Hohhot010021,China)(3DepartmentofCivilandEnvironmentalEngineering,UniversityofSouthFlorida,Tampa33620,USA)

Abstract:ToremedytheempiricalpitfallsofcurrentchinesespecificationsandMUTCD2009guidelinesindeterminingtheplacementdistanceoffreewayexitadvanceguidesigns,thedrivingmaneuverofexitingtrafficisanalyzedandthefactorsinfluencingplacementdistanceareexplored.Variablesincludingthenumberoflanes,lanewidth,lane-changingtime,driverpsvisualcharacteristics,signinstallationmethodsandoperatingspeedsonbothfreewaymainlinesandexitrampsarefoundsignificantinexplainingexitsafety.Threedifferentinstallationmethods,namelygroundinstallation,overheadinstallationandmedianinstallation,areintroducedandtheirapplicableconditionsaregiven.Models,withthesamestructureamongthethreeinstallationmethods,aredevelopedtocomputetheplacementdistanceunderdifferentroadwaygeometricandtrafficconditions.Takingoverheadinstallationasanexample,simulationresultsinTSIS-CORSIMshowthattheproposeddistancereducesthenumberoflanechangesintheareafromtherampnoseto500mupstreamby58193%comparedwithcurrentChinesespecificationsand27135%comparedwithMUTCD2009guidelines.Thus,thedistancesrecommendedinthispaperhaveabettersafetyperformance.Keywords:freeway;advanceguidesign;placementdistance;safetyimpac;tlanechange

Received2010-04-08.Biographies:GuoTangyi(1982)),male,graduate;DengWei(corre-spondingauthor),male,doctor,professor,dengwei@seu.edu.cn.Foundationitems:ProjectofFloridaDepartmentofTransportation(No.BD54438),theNationalKeyTechnologyR&DProgramofChinaduringthe11thFive-YearPlanPeriod(No.2006BAJ18B03).Citation:GuoTangy,iDengWe,iHouJiansheng,eta.lPlacementdis-tanceoffreewayexitadvanceguidesignanditssafetyimpacts[J].JournalofSoutheastUniversity(EnglishEdition),2010,26(4):622-627.

Advanceguidesigns(AGSs)playacrucialroleininfor-

mingdriversoftheexits,directingthemtodestinations,andgivingsuchgeneralinformationastohelpthemdriveinthemostsmipleanddirectmanner.ThemajoremphasesoffreewayAGSsarelaidondestinationsanddistances,whicharerepeatedlyprovidedinadvanceofexitramps[1].AmongtheserepeatedAGSs,theoneclosesttotheexitisthemostmiportantduetothefactthatifacarelessdrivermissesthissign,therearenomoresignsinforminghmiofhistargetexit.ProperlocationandinstallationofAGSsaremiportantinhelpingdriversfindtheirexactexitsonunfamiliarfreewaysandavoidproblemssuchasmissingtheexit,swervingab-ruptly,changinglanessharplyandothererraticmaneuvers. AccordingtoMUTCD2009,therearethreeinstallation

methodsofAGSs,namelygroundinstallation,overheadin-stallationandmedianinstallation,amongwhichtheformer

twoareoftenusedandtheotheroccasionally[2].WhereandhowtoinstalltheAGSdependsonlanduse,geometricdesignandtrafficcondition[3-4].Iftherearemorethanthreelanesonafreewaymainline,overheadinstallationisdesirable.Iftherequirementforsightdistancecannotbemetusinggroundin-stallation,overheadormedianinstallationispreferable.Me-dianinstallationisparticularlysuitableforleft-sideexitramps[5-6]. Asfortheplacementdistance,thereislittleresearchtore-

ferto.OnthefreewaysofChina,AGSsarerepeatedlyplacedthreetmies,generally500,1000,and1500minadvanceoftherampnose[7].InMUTCD2009,interchangesareclas-sifiedintotwocategories:major/intermediateinterchangeandminorinterchanges.TheplacementdistancesandrepeatedtmiesofAGSsaredeterminedaccordingtothesizesofthein-terchanges.Formajor/intermediateinterchanges,threeAGSsshouldbeinstalled,withthefirstsign015mile(018km),thesecondsign1mile(115km),andthethird210miles(310km)inadvanceoftherampnose.Forminorinterchan-ges,onlyoneAGSisrequiredtobeinstalledwith015to110mile(018to115km)inadvanceoftherampnose[2].FromthecurrentspecificationsinChinaandtheguidelinesinMUTCD2009,onecanseethefollowingthreeweaknesses:1)Boththeguidelinesareempiricism-based;2)InChina,placingAGSsatafixeddistanceinadvanceoftherampnoseislackofflexibility;3)InMUTCD2009,determiningtheplacementdistanceandthenumberofAGSsaccordingtothesizeofaninterchangeisarbitrary. Amiingatminmiizingtheweaknessesmentionedabove,we

presentmodelsfortheplacementdistanceofthreedifferentAGSinstallationmethods,consideringlane-changingbehav-ior,geometricdesign,andtrafficconditions.

1 AnalysisofExitingDrivingManeuver InFig.1,aneast-westboundfreewayonalevelterrainin-tersectsanorth-southboundarterialbyanexitramp,withtherightmostlanedirectinganexitramptothecrossroad.ThereisanexitsignindicatingthedistancefromtherampnosetothefirstAGS,whichistheclosestonetotherampnose.Theprmiaryobjectiveofthispaperistodeterminethisplacementdistance,labeledwithDpinFig.1.ThesignlocationsofthreedifferentinstallationmethodsareshowninFig.1,¹forgroundinstallation,ºforoverheadinstallationand»formedianinstallation. WhilemodelingtheAGSplacementdistance,weshould