土木工程 专业英语

LESSON1GENERALKNOWLEDGEOFROADSTEXTADEVELOPMENTOFROADSWHENWESPEEDALONGAMODERNHIGHWAY,WERARELYSTOPTOTHINKWHATITISWEARERIDINGONTOUNDERSTANDWHATAROADIS,WEMUSTSTUDYTHEWAYSINWHICHPEOPLEHAVETRAVELEDINTHEPASTTHEVERYFIRSTROADSWEREREALLYTRACKSBEATENINTHEGROUNDBYWILDANIMALSINPREHISTORICTIMESPEOPLEFOLLOWEDTHESEWINDINGTRAILSBECAUSETHEYPROVIDEDANEASYANDQUICKWAYTOGETTHROUGHTHICKFORESTSINTIME,PEOPLEBEGANTOIMPROVETHEPATHSBYFILLINGHOLESWITHEARTHANDLAYINGLOGSACROSSSOFT,BOGGYSPOTSTHESEATTEMPTSWERECRUDE,BUTTHEYWERETHEBEGINNINGOFROADCONSTRUCTIONASPEOPLEBEGANTOTRANSPORTGOODSOVERLONGERDISTANCES,THEYDEVELOPEDNEWWAYSOFTRAVELINGFIRSTTHEYPACKEDTHEIRWARESONANIMALSTHENTHEYINVENTEDVARIOUSKINDSOFSLEDSFINALLY,AFTERTHEINVENTIONOFTHEWHEEL,THEYBUILTWAGONSEACHADVANCEMENTBROUGHTANEEDFORBETTERTRAVELINGROUTESLATERINHISTORY,WHENWELLTRAVELEDROUTESWEREMADESTURDIERWITHROCKSANDSTONES,THEPATHWASRAISEDABOVETHESURROUNDINGLAND,ITBECAMEA“HIGHWAY”THEGREATCIVILIZATIONSTHROUGHOUTHISTORYWEREALSOTHEGREATROADSBUILDERSROADSWERENECESSARYTOCONTROLANDEXTENDEMPIRES,TOPERMITTRADEANDTRAVEL,ANDTOMOVEARMIESMOSTOFTHESEEARLYROADSWERESIMPLYHARDPACKEDDIRT,BUTSOMEWEREPAVEDWITHSTONEBLOCKSORBURNTBRICKSTHEROMANSBOUNDTHEIREMPIRETOGETHERWITHANEXTENSIVESYSTEMOFROADSRADIATINGINMANYDIRECTIONSFROMROMESOMEOFTHESEEARLYROADSWEREOFELABORATECONSTRUCTIONFOREXAMPLE,THEAPPIANWAY,BUILTSOUTHWARDABOUT312BC,ILLUSTRATESONEOFTHEPROCEDURESUSEDCYTHEROMESFIRSTATRENCHWASEXCAVATEDTOSUCHADEPTHTHATTHEFINISHEDSURFACEWOULDBEATGROUNDLEVELTHEPAVEMENTWASPLACEDINTHREECOURSEALAYEROFSMALLBROKENSTONES,ALAYEROFSMALLSTONESMIXEDWITHMORTARANDFIRMLYTAMPEDINTOPLACE,ANDAWEARINGCOURSEOFMASSIVESTONEBLOCKS,SETANDBEDDEDINMORTARSOMEOFTHEROMANROADSARESTILLINEXISTENCETODAYANDMANYMODERNHIGHWAYSFOLLOWTHEANCIENTROMANROUTESFEWROADSWEREBUILTDURINGTHEEARLYHISTORYOFTHEUNITEDSTATESSINCEMOSTOFTHEEARLYSETTLEMENTSWERECONNECTEDWITHTHENEARESTWHARF,BUTTHECONNECTINGROADUSUALLYWASJUSTACLEARINGTHROUGHTHEFORESTBEFORETHEREVOLUTIONARYWAR,TRAVELWASMAINLYONFOOTORHORSEBACK,ANDROADSWEREMERELYTRAILSCLEAREDTOGREATERWIDTHDEVELOPMENTWASEXTREMELYSLOWFORATIMEAFTERTHEWARSENDIN1783BETWEEN1795AND1830NUMEROUSTURNPIKES,PARTICULARLYINTHENORTHEASTERNSTATES,WEREBUILTBYCOMPANIESORGANIZEDTOGAINPROFITSTHROUGHTOLLCOLLECTIONSFEWOFTHEMWEREFINANCIALLYSUCCESSFULDURINGTHISPERIODMANYSTAGECOACHLINESANDFREIGHTHAULINGCOMPANIESWEREORGANIZEDTHEEXTENSIONOFTURNPIKESINTHEUNITEDSTATESWASABRUPTLYBYTHEDEVELOPMENTOFTHERAILROADSIN1830PETERCOOPERCONSTRUCTEDAMERICASFIRSTSTEAMLOCOMOTIVE,THETOMTHUMB,WHICHATONCEDEMONSTRATEDITSSUPERIORITYOVERHORSEDRAWNVEHICLESRAPIDGROWTHOFTHERAILROADFORTRANSPORTATIONOVERLONGDISTANCESFOLLOWEDCROSSCOUNTRYTURNPIKECONSTRUCTIONPRACTICALLYCEASED,ANDMANYALREADYCOMPLETEDFELLINTODISUSERURALROADSSERVEDMAINLYASFEEDERSFORTHERAILROADSIMPROVEMENTSPRIMARILYLEDTOTHENEARESTRAILROADSTATIONANDWEREMADELARGELYBYLOCALAUTHORITIESANDWERETOLOWSTANDARDSWHENITRAINED,THEROADSWERESLIPPERY,ANDINDRYWEATHERTHEYWEREDUSTYPEOPLEUSINGHORSESANDWAGONSACCEPTEDTHISBUTWITHTHEBEGINNINGOFTHE20THCENTURYANEWINVENTION,THEAUTOMOBILE,BEGANTOTAKEOVERTHEROADTHEFIRSTTWODECADESOFTHETWENTIETHCENTURYSAWTHEIMPROVEMENTOFTHEMOTORVEHICLEFROMA“RICHMANSTOY”TOAFAIRLYDEPENDABLEMETHODFORTRANSPORTINGPERSONSANDGOODSTHEREWERESTRONGDEMANDSNOTONLYFROMFARMERSBUTFROMBICYCLISTSTHROUGHTHELEAGUEOFAMERICANWHEELMENFORRURALROADIMPROVEMENT,LARGELYFORROADSAFEWMILESINLENGTHCONNECTINGOUTLYINGFARMSWITHTOWNSANDRAILROADSTATIONSTHISDEVELOPMENTHASBEENAPTLYDESCRIBEDAS“GETTINGTHEFARMEROUTOFTHEMUD”FROM1920TO1935,HIGHWAYDEVELOPMENTWASFOCUSEDPRIMARILYONTHECOMPLETIONOFANETWORKOFALLWEATHERRURALROADSCOMPARABLETOTHESTREETSYSTEMSUNDERTAKENBYLOCALGOVERNMENTSBY1935HIGHWAYACTIVITIESINRURALAREASHAVEBEENDEVOTEDMAINLYTOANATTEMPTTOPROVIDEFACILITIESOFHIGHERSTANDARDSANDWITHGREATERCAPACITYANDLOADCARRYINGABILITYDURINGTHESAMEPERIOD,INCREASINGATTENTIONHASBEENFOCUSEDONURBANAREAS,WHICHHAVEBEENSTRUCKSIMULTANEOUSLYBYRAPIDLYINCREASINGPOPULATION,LOWERPOPULATIONDENSITIESRESULTINGFROMA“FLIGHTTOTHESUBURBS”,ANDASHIFTFROMMASSTRANSPORTATIONTOTHEPRIVATEAUTOMOBILEINDICATIONSARETHATONLYMINORADDITIONSTOROADMILEAGEWILLBEMADEINTHEFUTURECOMPREHENSIVEEXERCISESPUTTHEFOLLOWINGCHINESEEXPRESSIONSINTOENGLISH,ORVICEVERSA运载能力LOADCARRYINGABILITY全天候道路ALLWEATHERROADS夯实土HARDPACKEDDIRT货运公司FREIGHTHAULING要求道路的改善DEMANDFORROADIMPROVEMENTATGROUNDLEVEL地面HORSEDRAWNVEHICLES马车APAVEMENTPLACEDINTHREECOURSES分三层建造道路INTHEFIRSTDECADEOFTHISCENTURY在这个世纪的头十年POPULATIONDENSITIES人口密度LESSON2SURVEYINGTEXTAAERIALSURVEYSAERIALPHOTOGRAPHS航空拍摄HAVEBECOMEMOSTVALUABLETOOLSINTHEHANDSOF在掌握之中THEHIGHWAYENGINEERTHEYAREVERYUSEFULVISUALAIDSINTECHNICALCONFERENCESANDATPUBLICHEARINGS,ANDTHEYAREALSOVERYVALUABLEINSEEKINGTHEMOSTSUITABLETOPOGRAPHICLOCATIONFORTHEHIGHWAYADDITIONALQUALIFYINGFACTORSWHICHCANBEDETERMINEDBYASKILLEDINTERPRETERAREASFOLLOW1LOCATESANDANDGRAVELDEPOSITS,BORROWPITS,ANDROCKAREASSUITABLEFORQUARRYING2RATESOILBEARINGCAPACITIESASGOOD,FAIRORPOOR3OUTLINESOILSASTOTHEIRTEXTURE,ANDESTIMATETHEDEPTHSOFORGANICDEPOSITS4CLASSIFYBEDROCKASTOPHYSICALTYPESANDTHEIRRELATIVEDEPTHSBELOWTHESURFACE5ESTIMATEDEPTHSOFGLACIALDRIFTANDWINDBLOWNMATERIAL6ESTIMATEHYDROLOGICALFACTORS7DELINEATEACTIVEANDPOTENTIALAREASINVOLVINGPROBLEMSSUCHASSINKHOLES,SLIDES,ROCKFALLSANDFROSTHEAVE8LOCATEUNDERGROUNDUTILITIESPLACEDBYCUTANDCOVERMETHODSNEWAERIALPHOTOGRAPHSPROVIDETHEMOSTUPTODATEINFORMATIONREGARDINGCURRENTLANDUSE,ANDTHISISOFPARTICULARIMPORTANCEATTHERECONNAISSANCEPHASEOFAHIGHWAYLOCATIONSTUDY,PARTICULARLYIFITISBEINGCARRIEDOUTINANURBANAREASIMILARLYTHESEPHOTOGRAPHSCANBEEASILYUSEDTOLOCATEIMPORTANTINTERMEDIATECONTROLPOINTS,SOTHATPOSSIBLEBANDROUTESCANBESELECTEDATTHISSTAGEOFTHERECONNAISSANCEASMALLSCALEMOSAICWILLPROVIDESUFFICIENTDETAILTOENABLEELIMINATIONOFALLBUTACOUPLEOFPOSSIBLEBANDSTOENABLETHECHOICETOBENARROWED,ANENLARGEDMOSAICCANBEVIEWEDINCONJUNCTIONWITHATOPOGRAPHICALMAPAUSEFULTECHNIQUEISTOASSEMBLEONEORMOREMOSAICBANDSANDTOOVERLAYTHEMWITHTOPOGRAPHICMAPSTHATAREENLARGEDTOTHESAMESCALEANDDRAWNONTRANSPARENTMATERIALTRIALLINESFOREACHROUTECANTHENBESKETCHEDONTHEMOSAICSANDPROFILESPLOTTED,DIRECTLYFROMTHECONTOURSOFTHEOVERLAYWHENROUTEPROFILESAREFOUNDWHICHINDICATEALIGNMENTSTHATMIGHTSATISFYTHEHIGHWAYSDESIGNSTANDARDS,THEYCANBECOMPAREDONABENEFITCOSTBASISTOAIDINTHEFINALSELECTIONLARGESCALEPHOTOGRAPHYISNECESSARYATBOTHTHEPRELIMINARYANDFINALLOCATIONPHASEOFALOCATIONSURVEYAIRPHOTOINTERPRETATIVEMETHODSCANBEUSEDTOCUTDOWNTHEAMOUNTOFSOILSURVEYFIELDWORKWHICHISNORMALLYCARRIEDOUTDURINGTHEFINALLOCATIONSURVEYASPARTOFTHEROUTINEFIELDSTUDIES,ITISCUSTOMARYTOCARRYOUTAUGERINVESTIGATIONSATFIXEDINTERVALSALONGTHELOCATIONLINE,ANDTHENTOCARRYOUTOTHERDETAILEDSTUDIESASINDICATEDBYTHERESULTSOBTAINEDMUCHOFTHISROUTINEAUGERINGANDSUBSEQUENTLABORATORYANALYSISMAYBEELIMINATEDIFTHEAIRPHOTOSAREUSEDTODELINEATEGROUNDAREASWITHSIMILARPHYSICALCHARACTERISTICSTHENITISONLYNECESSARYTOGOTOTHEFIELDANDTESTALIMITEDNUMBEROFPOINTSWITHINEACHDELINEATEDAREASIMILARLY,SOURCESOFSUITABLEAGGREGATESAREMOREEASIESDETERMINEDFROMTHEPHOTOGRAPHSANDTHEAMOUNTOFFIELDINVESTIGATIONANDLABORATORYTESTINGMINIMIZEDWHENLARGESCALEAERIALPHOTOGRAPHYISUSEDTOPREPARETHENECESSARYMAPS,ITMAYBEPOSSIBLETOCOMPLETETHEPLANSANDSPECIFICATIONSFORAHIGHWAYANDTOLETTHECONSTRUCTIONCONTRACTWITHOUTACTUALLYPLACINGACENTERLINEPEGINTHEGROUNDWHENTHISOCCURS,THEFINALLOCATIONLINENEEDNOTBEPEGGEDUNTILTHECONTRACTORISABOUTTOBEGINCONSTRUCTION,INWHICHCASETHEFINALLOCATIONSURVEYBECOMESACOMBINEDLOCATIONANDCONSTRUCTIONSURVEY新的空中拍摄的照片提供最先进的最新信息关于土地利用现状，这是特别重要的一条公路在侦察阶段的定位研究，特别是如果它是一个正在进行的市区了。同样这些照片可以很容易地用于定位的重要中间控制点，使可能带路线可以选择。在今年的侦察阶段的小型马赛克将提供足够的细节，让所有可能的消除，而是一个带夫妇。为了使选择收窄，扩大马赛克可以用地形图联系起来看。一个有用的技术是集合了一个或多个马赛克乐队，并与所覆盖的同等规模的扩大和透明材料绘制地形图他们。各条路线的试验线便可以勾勒的马赛克和绘制剖面，直接从覆盖的轮廓。当路线剖面发现这表明路线可能满足高速公路的设计标准，它们可以在一个比较效益费用的基础上，以帮助在最后的选择。大型摄影是需要在双方的初步和最后一个位置测量位置的阶段。空气照片解释性方法可以用来降低土壤的调查领域的工作通常是在最后的位置进行调查的数额。作为常规领域研究的一部分，这是习惯进行沿固定的时间间隔螺旋线的位置进行调查，然后进行结果表明所获得的其他详细研究。本例行AUGERING和实验室分析后，可消除大部分的航空照片，如果是用来划定具有类似的物理特性地面的地方。然后，它是唯一有必要到外地和测试每个划定区域内的点数量有限。同样，合适的骨料来源是从照片更EASIES决定和实地调查和实验室检测量减少。当大规模的空中摄影是用来准备必要的地图，它可能会完成的计划和一个高速公路的规格和让没有实际放置在地上一中心线挂施工合同。当发生这种情况，最终位置无须挂线，直至承包即将开始建设的，在这种情况下，最终成为一个联合调查地点的位置和施工测量。LESSON8TRAFFICSTREAMCHARACTERISTICSTEXTABASICPARAMETERSOFTRAFFICSTREAMVOLUMETRAFFICSTREAMPARAMETERSFALLINTOTWOBROADCATEGORIESMACROSCOPICPARAMETERSCHARACTERIZETHETRAFFICSTREAMASAWHOLEMICROSCOPICPARAMETERSCHARACTERIZETHEBEHAVIOROFINDIVIDUALVEHICLESINTHETRAFFICSTREAMWITHRESPECTTOEACHOTHERATRAFFICSTREAMMAYBEDESCRIBEDMACROSCOPICALLYBYTHREEPARAMETERS1VOLUMEORRATEOFFLOW2SPEED3DENSITYVOLUMETRAFFICVOLUMEISDEFINEDASTHENUMBEROFVEHICLESTHATPASSAPOINTONAHIGHWAY,ORAGIVENLANEORDIRECTIONOFAHIGHWAY,DURINGASPECIFIEDTIMEINTERVALTHEUNITFORVOLUMEISSIMPLY“VEHICLES”,ALTHOUGHITISOFTENEXPRESSEDASVEHICLESPERUNITOFTIME1DAILYVOLUMEANDTHEIRUSEACOMMONTIMEINTERVALFORVOLUMESISADAYDAILYVOLUMESAREFREQUENTLYUSEDASTHEBASISFORHIGHWAYPLANNINGANDGENERALOBSERVATIONSOFTRENDSTRAFFICVOLUMEPROJECTIONSAREOFTENBASEDUPONMEASUREDDAILYVOLUMESFOURDAILYPARAMETERSAREWIDELYUSED1AVERAGEANNUALDAILYTRAFFICAADTISTHEAVERAGE24HOURTRAFFICVOLUMEATAGIVENLOCATIONOVERAFULL365DAYSYEARSTHATIS,THETOTALNUMBEROFVEHICLESPASSINGTHESITEINAYEARDIVIDEDBY3652AVERAGEANNUALWEEKDAYTRAFFICAAWTISTHEAVERAGE24HOURTRAFFICVOLUMEOCCURRINGONWEEKDAYSOVERAFULLYEARTHISVOLUMEISOFCONSIDERABLEINTERESTWHEREWEEKENDTRAFFICISLIGHT,SOTHATAVERAGINGHIGHERWEEKDAYVOLUMESOVER365DAYSWOULDMASKTHEIMPACTOFWEEKDAYTRAFFICAAWTISCOMPUTEDBYDIVIDINGTHETOTALWEEKDAYTRAFFICVOLUMEFORTHEYEARBY2603AVERAGEDAILYTRAFFICADTISANAVERAGE24HOURTRAFFICVOLUMEATAGIVENLOCATIONFORSOMEPERIODOFTIMELESSTHANAYEARWHILEANAADTISFORAFULLYEAR,ANADTMAYBEMEASUREDFORSIXMONTH,ASEASON,AMONTH,AWEEK,ORASLITTLEASTWODAYSANADTISAVALIDNUMBERONLYFORTHEPERIODOVERWHICHITWASMEASURED4AVERAGEWEEKDAYTRAFFICAWTISANAVERAGE24HOURTRAFFICVOLUMEOCCURRINGONWEEKDAYSFORSOMEPERIODOFTIMELESSTHANONEYEAR,SUCHASAMONTHORASEASONTHERELATIONSHIPBETWEENAAWTANDAWTISANALOGOUSTOTHATBETWEENAADTANDADTTHEUNITBYWHICHALLOFTHESEVOLUMESAREDESCRIBEDISVEHICLESPERDAYVPDDAILYVOLUMESGENERALLYARENOTDIFFERENTIATEDBYDIRECTIONORLANEBUTARETOTALSFORANENTIREFACILITYATTHESPECIFIEDLOCATION2HOURLYVOLUMESANDTHEIRUSEWHILEDAILYVOLUMESAREUSEFULINHIGHWAYPLANNING,THEYCANNOTBEUSEDALONEFORDESIGNOROPERATIONALANALYSISPURPOSESVOLUMEVARIESCONSIDERABLYDURINGTHECOURSEOFA24HOURDAY,USUALLYWITHPERIODSOFMAXIMUMVOLUMEOCCURRINGDURINGTHEMORNINGANDEVENINGCOMMUTER“RUSH”HOURTHESINGLEHOUROFTHEDAYTHATHASTHEHIGHESTHOURLYVOLUMEISREFERREDTOASTHE“PEAKHOUR”ITISTHETRAFFICVOLUMEWITHINTHISHOURTHATISOFGREATESTINTERESTTOASTRAFFICENGINEERSINDESIGNOROPERATIONALANALYSISTHEPEAKHOURVOLUMEISGENERALLYADIRECTIONALVOLUMETHATIS,AVOLUMEINWHICHTHEDIRECTIONSOFFLOWARESEPARATEDPEAKHOURLYVOLUMESAREUSEDASTHEBASISFORHIGHWAYDESIGNANDFORMANYTYPESOFOPERATIONALANALYSISHIGHWAYSMUSTBEDESIGNEDTOADEQUATELYSERVETHEPEAKHOURTRAFFICVOLUMEINTHEPEAKDIRECTIONOFFLOWSINCETHISTRAFFICGENERALLYTRAVELSONEWAYINTHEMORNINGANDTHEOTHERATNIGHT,BOTHDIRECTIONSOFTHEFACILITYARENORMALLYDESIGNEDTOACCOMMODATETHEDIRECTIONALPEAKHOURVOLUMEMOSTOPERATIONALANALYSES,WHETHERCONCERNINGIMPOSITIONOFCONTROLMEASURES,SAFETY,ORCAPACITY,MUSTADDRESSCONDITIONSEXISTINGDURINGPERIODSOFPEAKTRAFFICVOLUMEPEAKHOURLYVOLUMESAREUSEFULFORTHISPURPOSE,ASARESUBHOURLYFLOWSTOBEDISCUSSEDINTHENEXTSECTIONINDESIGN,PEAKHOURLYVOLUMESARESOMETIMESESTIMATEDFROMDAILYVOLUMEPROJECTIONS,USINGTHEFOLLOWINGRELATIONSHIPDDHVAADTKDWHEREDDHVDIRECTIONALDESIGNHOURVOLUMEVPHAADTAVERAGEANNUALDAILYTRAFFICVPDKTHEPROPORTIONOFDAILYTRAFFICOCCURRINGDURINGTHEPEAKHOUR,EXPRESSEDASADECIMALDTHEPROPORTIONOFPEAKHOURTRAFFICTRAVELINGINTHEPEAKDIRECTION,EXPRESSEDASADECIMALFORDESIGNPURPOSES,KOFTENREPRESENTSTHEPROPORTIONOFAADTOCCURRINGDURINGTHETHIRTIETHHIGHESTPEAKHOUROFTHEYEARTHEPEAKHOURSVARYFOREACHDAYANDMAYBERANKEDINORDEROFDECREASINGVOLUMETHETHIRTIETHHIGHESTPEAKHOURVOLUMEINSUCHALISTINGISACRITERIONOFTENUSEDFORRURALDESIGNANDANALYSISOTHERS,SUCHASTHEFIFTIETH,ARESOMETIMESUSEDINURBANSITUATIONSTHEKANDDFACTORSUSUALLYARECOMPUTEDBASEDUPONLOCALORREGIONALCHARACTERISTICSATEXISTINGLOCATIONSINGENERAL,THEKFACTORDECREASESASTHEDENSITYOFDEVELOPMENTSURROUNDINGTHEHIGHWAYINCREASESINDENSERAREAS,THEREISMOREOFFPEAKTRAFFIC,ANDCAPACITYDEFICIENCIESTENDTOSPREADDEMANDACROSSALONGERPERIODTHANINMORESPARSELYDEVELOPEDAREASTHEDFACTORISMOREVARIABLEITDEPENDUPONDEVELOPMENTDENSITYANDUPONTHESPECIFICRELATIONSHIPOFTHEFACILITYINQUESTIONTOMAJORTRAFFICGENERATORSINTHEAREATABLE81GIVESGENERALRANGESFORTHESEFACTORSASANILLUSTRATION交通流参数可分为两大类宏观参数描述作为一个整体的交通流微观参数的交通流特征与相互尊重的个别车辆的行为。阿交通流可能是从宏观上描述了三个参数1体积或流速2SPEED3DENSITYVOLUME交通量被定义为通过的车辆在高速公路上，或某一线或公路的方向点在指定的时间间隔，数量。对于体积单位是简单的“车辆”，尽管它经常被车辆表示每单位时间。1。日均交易量与使用一个共同的时间间隔是量一天。每日量经常作为公路的规划和趋势一般性意见的基础。交通量的预测往往是基于每日量测。每天4个参数，广泛应用于（一）年平均每日流量（AADT）是平均24小时，比1365天，年满某一地点的交通量即在通过在除以365年地盘车辆总数。（2）平均每年平日交通（AAWT）是平均24小时交通量较平日全年发生。本卷是相当感兴趣的地方是周末交通灯，使平均高出365天工作日量会掩盖平日交通的影响。AAWT是除以260计算的总工作日全年交通量。（3）平均每日交通（ADT）的是一个平均24小时为一段时间不到一年的时间特定地点的交通流量。虽然一AADT为全年就是一个ADT可能为6个月来衡量，一个赛季，一个月，一周，还是很少，两天。一个ADT是一个只有在它的有效期是衡量数量。（4）平均平日交通（AWT的）是平均24小时交通量为平日一段时间发生不到一年，如一个月或一个赛季。之间AAWT和AWT之间的关系类似于AADT和ADT了这一点。利用这些都说明这些量的单位是每天的车辆（VPD的）。每日量一般都没有方向或行车区别，但在指定的位置对整个设施总数。2。每小时卷及其使用虽然每天都在公路的规划量有用，但不能单独使用，设计或运作分析的目的。音量相差很大，在一个24小时工作制的过程通常与最大音量的时期，在早上和晚上下班发生“火拼”一小时。这一天具有最高每小时单量每小时称为“繁忙时间”。它是在这一小时是最感兴趣的是交通量在设计或操作分析交通工程师。在繁忙时间量通常是一个方向性的量即在其中流动的方向是分开的音量。高峰每小时卷是用作公路设计的基础和多种类型的业务分析。公路设计必须充分服务的方向流动高峰高峰小时交通量。由于该旅游交通一般在早上一晚上的方法和其他有关设施的设计通常都是以适应定向高峰小时容量的方向。大部分业务分析，就是否实施控制措施，安全，或能力，必须在现有条件下解决高峰时段交通量。高峰每小时产量是有益的这一目的，因为要在下一节讨论SUBHOURLY流动。在设计，高峰每小时量有时从日交易量估计预测，使用下面的关系DDHVAADT深K表其中DDHV定向设计小时量（VPH）AADT年平均每日交通（VPD的）K二，每日交通高峰期间发生的比例时，作为一个十进制表示在繁忙时间在交通高峰方向行驶的比例，表示为一个小数为设计目的，钾往往代表了AADT比例在第三十届最高的一年繁忙时间发生。在繁忙时间不尽相同，每一天，可能是为了排名的下降量。第三十届最高峰小时的这种上市量往往是农村的设计和分析用的标准。其他如五十，有时在市区情况下使用。的K和D的因素通常是计算依据当地或在现有地点的区域性特征。一般来说，与周围的公路增加开发密度K因子减少。在密集的地区，有更多的非高峰期的交通和能力不足往往分散在一个较长时期的需求比发达地区更稀少。D的因素是多变量，它在发展密度，并呼吁对有关设施的具体关系在该地区的主要交通发电机依赖。表81给出了一个例子，这些因素的综合范围。TABLE81GENERALRANGESFORKANDDFACTORSFACILITYTYPENORMALRANGEOFFACTORSKFACTORDFACTORRURAL015025065080SUBURBAN012015055065URBANRADIALROUTE007012055060CIRCUMFERENTIALROUTE0070120500553SUBHOURLYVOLUMESANDRATESOFFLOWTHEQUALITYOFTRAFFICFLOWISOFTENRELATEDTOSHORTTERMFLUCTUATIONSINTHETRAFFICDEMANDAFACILITYMAYHAVECAPACITYADEQUATETOSERVETHEPEAKHOURDEMAND,BUTSHORTTERMPEAKSOFFLOWWITHINTHEPEAKHOURMAYEXCEEDCAPACITY,THEREBYCREATINGABREAKDOWNVOLUMESOBSERVEDFORPERIODSOFTIMELESSTHANONEHOURAREGENERALLYEXPRESSEDASEQUIVALENTHOURLYRATESOFFLOWFOREXAMPLE,1000VEHICLESOBSERVEDINA15MINUTEPERIODWOULDBEEXPRESSEDASVPHHRE40251THERELATIONSHIPBETWEENHOURLYVOLUMEANDMAXIMUMRATEOFFLOWWITHINTHEHOURISDEFINEDTHEPEAKHOURFACTORPHF,ASFOLLOWSFLOWRATEIMUVHOLYPHFX15MINUTEPERIODSOFFLOW,THEEQUATIONBECOMES154VHPFWHEREHVHOURLYVOLUMEVPHMAXIMUM15MINUTEVOLUMEWITHINTHE15VHOURVEHLESSON9HIGHWAYCAPACITYANDSAFETYTEXTACONCEPTSOFCAPACITYANDLEVELOFSERVICECAPACITYTHE1985HIGHWAYCAPACITYMANUALDEFINEDTHECAPACITYOFAFACILITYAS“THEMAXIMUMHOURLYRATEATWHICHPERSONSORVEHICLESCANREASONABLYBEEXPECTEDTOTRAVERSEAPOINTORUNIFORMSEGMENTOFALANEORROADWAYDURINGAGIVENTIMEPERIODUNDERPREVAILINGTRAFFIC,ROADWAY,ANDCONTROLCONDITIONS”SEVERALKEYPOINTSINTHISDEFINITIONREQUIREEMPHASIS1THECAPACITYOFAFACILITYISDEPENDENTUPONPREVAILINGCONDITIONSTRAFFICCONDITIONSREFERPRIMARILYTOTHECOMPOSITIONOFTRAFFICUSINGTHEFACILITIES,GENERALLYEXPRESSEDASTHEPROPORTIONOFPASSENGERCARS,TRUCKS,BUSES,ANDRECREATIONALVEHICLESINTHETRAFFICSTREAMROADCONDITIONSREFERTOTHEGEOMETRICCHARACTERISTICSOFTHEROADWAY,SUCHASDESIGNSPEED,HORIZONTALANDVERTICALALIGNMENT,NUMBERANDWIDTHOFLANES,LATERALCLEARANCES,ANDLANECONFIGURATIONCONTROLCONDITIONSREFERTOTHEPRESENCEOFCONTROLSTHATIMPACTROADWAYUTILIZATION,SUCHASSIGNALS,STOPANDYIELDSIGNS,LANEUSECONTROLS,ONEWAYSTREETSANDOTHERSACHANGEINPREVAILINGCONDITIONSWILLRESULTINACHANGEINCAPACITY2CAPACITYREFERSTOA“POINTORUNIFORMSEGMENT”OFTHEFACILITYCAPACITYANALYSISISCONDUCTEDFORSEGMENTSOFAFACILITYHAVINGUNIFORMTRAFFIC,ROADWAY,ANDCONTROLCONDITIONSBECAUSECAPACITYDEPENDSONTHESEFACTORS,SEGMENTSHAVINGDIFFERENTPREVAILINGCONDITIONSWILLHAVEDIFFERENTCAPACITIES3CAPACITYISTHEMAXIMUMRATEOFFLOW,WHICHTHEFACILITYCANACCOMMODATETHEPERIODOFANALYSISFORMOSTCAPACITYANALYSESISAPEAK15MINUTEPERIODWITHINTHEHOUROFINTERESTCAPACITYREFERSTOTHEMAXIMUMRATEOFFLOWTHATCANBEACCOMMODATEDWITHINSUCHA15MINUTEPERIOD,NOTTOTHEMAXIMUMHOURLYVOLUMETHATCANBEACCOMMODATEDWITHINAFULLHOUR4CAPACITYISDEFINEDONTHEBASISOF“REASONABLEEXPECTANCY”THATIS,ASTATEDCAPACITYFORAGIVENFACILITYISARATEOFFLOWTHATCANBEREPEATEDLYACHIEVEDDURINGEVERYPEAKPERIODFORWHICHSUFFICIENTDEMANDEXITSANDTHATCANBEACHIEVEDONANYFACILITYWITHSIMILARCHARACTERISTICSANYWHEREWITHINNORTHAMERICAITISNOTTHEABSOLUTEMAXIMUMRATEOFFLOWEVEROBSERVEDONSUCHAFACILITYDRIVERCHARACTERISTICSVARYFROMPLACETOPLACE,ANDINDEEDCAPACITYOFAFACILITYISTHATMAXIMUMRATEOFFLOWWHICHTHETRAFFICENGINEERMAYBEREASONABLYASSUREDOFBEINGABLETOACHIEVEDAYINANDDAYOUTANYWHEREINNORTHAMERICAITMEANS,HOWEVER,THATOCCASIONALLYMEASUREDRATESOFFLOWATCRITICALLOCATIONSWILLEXCEEDTHETEXTBOOKORDEFINED“CAPACITY”OFTHEFACILITYSUCHRATES,HOWEVER,AREOFTENNOTSUSTAINABLEORCANNOTBEACHIEVEDREPEATEDLYORATSIMILARLOCATIONSINOTHERPARTSOFNORTHAMERICA5CAPACITYMAYBEDEFINEDINTERMSOFPERSONS/HOURORVEHICLES/HOUR,DEPENDINGUPONTHETYPEOFFACILITYINVOLVEDTHE1985HIGHWAYCAPACITYMANUALINCLUDESPROCEDURESADDRESSINGPEDESTRIANANDTRANSITFACILITIES,FORWHICHCAPACITIESAREDEFINEDINTERMSOFPERSONS/HOURFOROTHERTYPESOFFACILITIES,CAPACITYISGENERALLYDEFINEDINTERMSOFVEHICLES/HOURFORTHEPREVAILINGMIXOFVEHICLESTHECAPACITYOFAHIGHWAYFACILITYISANIMPORTANTCHARACTERISTICOPERATINGCONDITIONSATCAPACITYARE,HOWEVER,GENERALLYPOORFEWFACILITIESAREDESIGNEDTOOPERATEATORNEARCAPACITYBECAUSEOFPOOROPERATINGCHARACTERISTICSANDTHEDIFFICULTYINMAINTAININGCAPACITYOPERATIONSWITHOUTBREAKDOWNTHUS,THEABILITYTOANALYZETHETRAFFICCARRYINGABILITYOFFACILITIESUNDERBETTEROPERATINGCONDITIONSISAMAJORASPECTOFCAPACITYANALYSISTHELEVELOFSERVICEALEVELOFSERVICEISALETTERDESIGNATIONTHATDESCRIBESARANGEOFOPERATINGCONDITIONSONAPARTICULARTYPEOFFACILITYTHE1985HIGHWAYCAPACITYMANUALDEFINESTHELEVELOFSERVICECONCEPTAS“AQUALITATIVEMEASUREDESCRIBINGOPERATIONALCONDITIONSWITHINATRAFFICSTREAMANDTHEIRPERCEPTIONBYMOTORISTSAND/ORPASSENGERS”THECRITICALPOINTINTHISDEFINITIONISTHENEEDTODEFINESERVICEQUALITYINTERMSTHATAREPERCEIVEDBYDRIVERSANDPASSENGERSSEVERALKEYMEASURESAREUSEDINTHE1985HIGHWAYCAPACITYMANUALTODESCRIBESERVICEQUALITYINTHESETERMS1SPEEDANDTRAVELTIMEONEOFTHEMOSTEASILYPERCEIVEDMEASURESOFSERVICEQUALITYISSPEED,ORITSINVERSE,TRAVELTIMEDRIVERSAND