畢業設計（論文）外文資料翻譯系別： 土木系 專業： 土木工程（道橋方向） 班級： 工077 姓名： 學號： essiishvil gieerig ecaics 附 指導教師評語指導教師評語：簽字： 年 月日1、 外文原文（復印件）Theroad(highway)Theroadisonekindoflinearconstructionusedfortravel.Itismadeoftheroadbed,theroadsurface,thebridge,theculvertandthetunnel.Inaddition,italsohasthecrossingoflines,theprotectiveprojectandthetrafficengineeringandtheroutefacility.Theroadbedisthebaseofroadsurface,roadshoulder,sideslope,sideditchfoundations.Itisstonematerialstructure,whichisdesignedaccordingtoroute'splaneposition.Theroadbed,asthebaseoftravel,mustguaranteethatithastheenoughintensityandthestabilitythatcanpreventthewaterandothernaturaldisasterfromcorroding.Theroadsurfaceisthesurfaceofroad.Itissingleorcomplexstructurebuiltwithmixture.Theroadsurfacerequirebeingsmooth,havingenoughintensity,goodstabilityandanti-slipperyfunction.Thequalityofroadsurfacedirectlyaffectsthesafe,comfortandthetraffic.Theroutemarkingisonekindoftrafficsafetyfacilitypaintedbyoilpaintormadebytheconcreteandtilesonhigh-level,lesshigh-typesurface.Itsfunctioniscoordinatingthesigntomaketheeffectivecontroltothetransportation,directingthevehiclesskiproadtravel,servingunimpededandthesafepurpose.Ourcountryroadroutemarkinghasthelanemedianline,thetrafficlaneboundary,thecurbline,theparkingline,theconductioncurrentbelt,thepedestriancrossingline,thefourcornerscentercircle,theparkingazimuthline.Theroutemarkinghasthecontinualsolidline,thebrokenlineandthearrowindicatoranditscolorusesthewhiteortheyellow.Thearchofbridgeisthestructurewhichstridesoverrivers,mountainvalleyandchannel.Itismadegenerallybysteelrod,concreteandstone.Thetunnelisthecavewhichconnectsbothsidesoftheroad.Thetechniqueofthisconstructionisverycomplex,thecostoftheprojectsishigherthancommonroad.However,itreducesthedrivingdistancebetweentwoplaces,enhancesthegradeofthetechnicalinbuildingtheroadandguaranteesthecarscandrivefastandsafely,thusreducesthecostoftransportation.Theprotectiveprojectistoprotectandconsolidatetheroadbedinorderthatitcanguaranteetheintensityandthestabilityoftheroad,thusmaintainstheautomobiletopassthroughsafely.Inordertoguaranteethatsafeoperationofthehighwaytransportation,besidesthehighwayengineeringandthevehiclesperformance,itmusthavesometrafficsignal,routemarking,eachkindofdirectoranddemonstratefacility.Thehighwaymarkingusescertainmarkanddrawsymbol,simplewordsandnumber,theninstallsinthesuitableplacetoindicatethefrontroad'sconditionortheaccidentconditionincludingtheinformationalsign,thewarningsignal,theprohibitorysign,theroadsignandsoon.TheroadwhichJoincity,villageandindustry,mainlyareusedfortheautomobileandhascertaintechnicalstandardandthefacilitypathcanbecalledthehighway.hehighway”inChineseisthemodernview,butitwasnotexistedinoldday.Itgetsthenamefromthemeaningofbeingusedforthepublictraffic.Wherearethehuman,therearetheroad.Itisatruth.However,theroadisnotthehighway.Ifwetalkthehistoryabouttheroad,theearliesthighwayisthatbuiltbytheoldEgyptiansformakingthepyramid.NextisthestreetwhichbuiltbytheBabylonpeopleabout4000yearsago.Allthesearemuchearlierthanourcountry.About500B.C.,thePersianEmpireroadhaslinkedupEastandWest,andconnectedtheroadtoChina.ItistheearliestandlongestSilkRoad.2500yearsago,itmightbethegreatestroad.TheancientRomeEmpireroadwasoncecelebrated;ittookRomeasthecenter,allaroundbuilt29roads.Thereforeitcameoutonecommonsaying:everyroadleadstoRome.Theroad'sconstructionistheprocesstoenhancetechniqueandrenewthebuildingmaterials.Theearliestistheoldroad,itiseasytobuildbutitisalsotodestroy.Ifthereistoomuchwaterorcars,itwillbeunevenandevenbedestroyed.ThemacadamroadappearedintheEuropewhichoutbalancedtheearliestmudroad.ThenthebrickroadappearedwhichwasearlierthanChina.Itwasonegreatbreachthatwemoldedbitumenonthemacadamroad.Fromancienttimestothepresent,Chinahascourierstationandcourierroad,whilethefirstmoreadvanceroadwastheonethatfromLongZhouinGangXitoZhenNanGuanin1906.ThedifferencebetweenRoadandpathThepathistheprojectforeachkindofvehiclesandpeopletopassthrough.Accordingtoitsfunction,wecandivideitintotheurbanroad,theroad,thefactoriesandminespath,theforestroadandcountyroad.TheclassificationofroadFirst,accordingtoadministrativerank,itincludesnationalhighway,provinceroad,countyroadandthespecialroad.Generallythenationalhighwayandprovinceroadarenamedmainline;thecountyroadisnamedbranchline.Thenationalroadisthemainlineandhaspoliticalandeconomysignificance,includingtheimportantnationaldefenseroadandtheroadcollectingourcapitalwithotherprovinces,autonomousregionsandmunicipalities.Itisalsotheroadlinkstheeconomycenter,seaporthinge,factoryandimportantstrategicplace.Thehighwaystridingoverdifferentprovincesarebuilt,protectedandmanagedbythespecialorganizationswhichareapprovedbytheministryofcommunications.Theprovincialroadisthemainlinebuilt,protected,managedbytheroadmanagedepartment.Itisfullofpoliticalandeconomicsensetothewholeprovince.Thesinglewayfourlevelsofroadscanadaptbeloweachdayandnightmedium-dutytruckvolumeoftraffic200.Thecountyrouteisreferstohascounty-wide(county-levelcity)politics,theeconom-icsignificance,connectsinthecountyandthecountythemaintownship(town),theprin-cipalcommoditiesproductionandthecollectionanddistributioncenterroad,aswellasdoesnotbelongtothefederalhighway,provincialroad'scountybordertheroad.Thecoun-tyroutebythecounty,thecityroadDepartmentresponsiblefortheworkisresponsibletoconstruct,themaintenanceandthemanagement.Thetownshiproadreferstomainlytheroadwhichforthetownship(town)thevilla-geeconomy,theculture,theadministrationserves,aswellasdoesnotbelongtoabovet-hecountyroutebetweenroad'stownshipandthetownshipandthetownshipandtheexte-riorcontactroad.Townshipisresponsiblebythepeople'sgovernmenttoconstruct,them-aintenanceandthemanagement.Thespecial-purposeroadisreferstofeedsspeciallyormainlysuppliesthefactoriesandmines,theforestregion,thefarm,theoilfield,thetouristarea,themilitaryimportantplaceandsoonandtheexternalrelationsroad.Thespecial-purposeroadisresponsiblebythespecial-purposeunittoconstruct,themaintenanceandthemanagement.Mayalsoentrustthelocalroaddepartmenttoconstruct,themaintenanceandthemanagement.Second,accordingtotheuseduty,thefunctionandadaptsthevolumeoftrafficdivision.Accordingtoourcountrypresent"HighwayengineeringTechnicalstandard"theroadaccordingtotheuseduty,thefunctionandtheadaptationvolumeoftra-fficdividesintohighway,arterialroad,second-classroad,tertiaryhighway,fourlevelofroadfiveranks:1st,thehighwaytofeedspeciallytheautomobileandshouldcontrolthedifferencec-ompletelyrespectivelytowardthedividingstriponroadstravelthemultiplehighway.Thefourtrafficlanehighwaysoughttobeabletoadapteachkindofautomobilereducepassengervehicle'syearmeandiurnalvolumeoftraffic25000~55000.Thesixtrafficlanehighwaysoughttobeabletoadapteachkindofautomobilereducepassengervehicle'syearmeandiurnalvolumeoftraffic45000~80000.Theeighttrafficlanehighwaysoughttobeabletoadapteachkindofautomobiler-educepassengervehicle'syearmeandiurnalvolumeoftraffic60000~100000.2nd,thearterialroadtosupplytheautomobileandmayaccordingtoneedtocontrolthedifferencerespectivelytowardthedividingstriponroadstravelthemultiplehighway.Thefourtrafficlanearterialroadsoughttobeabletoadapteachkindofautomobilreducepassengervehicle'syearmeandiurnalvolumeoftraffic15000~30000.Thesixtrafficlanearterialroadsoughttobeabletoadapteachkindofautomobilereducepassengervehicle'syearmeandiurnalvolumeoftraffic25000~55000.3rd,thesecond-classroadtosupplytheautomobiletravelthetwo-lanehighway.Canadapteachdayandnights3000~7500medium-dutytruckvolumeoftrafficgenerally.4rd,tertiaryhighwaystomainlysupplytheautomobiletravelthetwo-lanehighway.Canadapteachdayandnights1000~4000medium-dutytruckvolumeoftrafficgenerally.The5,fourlevelsofroadstomainlysupplytheautomobiletravelthetwo-laneorthesingle-lanehighway.Thetwo-lanefourlevelsofroadscanadaptbeloweachdayandnightmedium-dutytruckvolumeoftraffic1500.HighwayengineeringincludesHighwayplanninglocationdesignandmaintenance.BeforethedesignandconstructionofanewhighwayorhighwayimprovementcanbeundertakentheremintbegeneralplaningandconsiderationoffinancingAspartofgeneralplanningitisdecidedwhatthetrafficneedofthereawillbeforaconsiderableperiod,generally20years,andwhatconstructionwillmeetthoseneeds.Toassesstrafficneedsthehighwayengineercollectsandanalyzesinformationaboutthephysicalfeaturesofexistingfacilities,thevolume,distribution,andcharacterofpresenttraffic,andthechangestobeexpectedinthesefactor.Thehighwayengineermustdeterminethemostsuitablelocationlayout,andcapacityofthenewrouteandstructures.Frequently,apreliminarylineorlocationandseveralalternateroutesarestudied.Thedetaileddesignisnormallybegunonlywhenthepreferredlocationhasbeenchosen.Inselectingthebestroute,carefulconsiderationisgiventothetrafficrequirementsterraintobetraversedvalueoflandneededfortheright-of-way.andestimatedcostofconstructionforthevariousplans.Thephotogrammetricmethod,whichmakesuseofaerialphotographsisusedextensivelytoindicatethecharacteroftheterrainonlargeprojectswhereitismosteconomical.Onsmallproject,Financingconsiderationsdeterminewhethertheprojectcanbecarriedoutonetimeorwhetherconstructionmustbeinstageswitheachstageinitiatedasfundsbecomeavailable.Indecidingthebestmethodoffinancingthework,theengineermakesananalysisofwhomitwillbenefit.Importanthighwaysandstreetsbenefit*invaryingdegrees,threegroups*usersownersofadjacentpropertyandthegeneralpublic.Usersofimprovedhighwaysbenefitfromdecreasedcostoftransportation,greatertravelcomfort,increasedsafetyandsavingoftime.Theyalsoobtainrecreationalandeducationalbenefits.Ownersofabuttingoradjacentpropertymaybenefitfrombetteraccess,increasedpropertyvalue,moreeffectivepoliceandfireprotection,improvedstreetparkinggreaterpedestriantrafficsafety,andtheuseofthestreetright-of-wayforthelocationofpublicutilitiessuchaswaterlinesandsewers.Evaluationofvariousbenefitsfromhighwayconstructionisoftendifficultbutisamostimportantphaseofhighwayengineering.Somebenefitscanbemeasuredwithaccuracy,buttheevaluationofothersismorespeculative.Asaresultnumerousmethodsarcusedtofinanceconstruction,andmuchengineeringworkmayheinvolvedinselectingthebestprocedure.Environmentalevaluation.Theenvironmentalimpactofconstructinghighwayshasreceivedincreasedattentionandimportance.Manyprojectshavebeendelayedandnumerousotherscanceledbecauseotenvironmentalproblems.Theenvironmentalstudyorreportcoversmanyfactors,includingnoisegeneration,airpollutiondisturbanceofareastraverseddestructionofexistinghousingandpossiblealternateroutes.Highwayengineersmustalsoassistintheacquisitionofright-of-wayneededfornewhighwayfacilitiesAcquisitionofthelandrequiredforconstructionofexpresswaylendingintothecentralbusinessareasofcitieshasprovedextremelydifficultithepublicisdemandingthattrafficengineersworkcloselywithcityplanners,architects,sociologistsandallgroupsinterestedinbeautificationandimprovementofcitiestoassurethatexpresswaysextendinxthroughmetropolitanareasbebuiltonlyaftercoordinatedevaluationofallmajorquestions,includingthefollowing;(1)Issufficientattentionbeingpaid-tobeautificationoftheexpresswayitself?(2)Wouldachangeinlocationpreservemajornaturalbeautiesofthecity?(3)Couldadepresseddesignhelogicallysubstitutedforthosesectionswhereanelevatedexpresswayisproposed?(4)Canthegeneraldesignheimprovedtoreducethenoisecreatedbylargevolumesoftraffic?(5)Aresomesectionsofthecitybeingisolatedbytheproposedlocation?Detaileddesign.Detaileddesignofahighwayprojectincludespreparationofdrawingsorblueprintstobeusedforconstruction.Theseplansshow,forexample,thelocation,thedimensionsofsuchelementsasroudwaywidth*thefinajprofilefor(heroad,thelocationandtypeofdrainagefacilities,andthequantitiesofworkinvolved,includingearthworkandsurfacing.Inplanningthegradingoperationsthedesignengineerconsidersthetypeofmaterialtobeencounteredinexcavatingorincuttingawaythehighpointsalongtheprojectandhowthernaterialremovedcanbestbeutilisedforfillorforconstructingembankmentsacrosslowareaselsewhereontheproject.Forthistheengineermustanalyzethegradationandphysicalpropertiesofthesoil,determinehowtheembankmentscanbestbecompacted,andcalculatethevolumeofearthworktobedone.Electroniccalculatingproceduresarenowsometimesusedforthelaststep.Electronicequipmenthasalsospeededupmanyotherhighwayengineeringcalculations.PowerfulandhighlymobileearthmovingmachineshavebeendevelopedTOpermitrapidandeconomicaloperations.,Selectionofthetypeandthicknessofroudwaysurfacingtobeconstructedisanimportantpartofdesign.Thetypechosendependsuponthemaximumloadstobeaccommodated,thefrequencyoftheseloadsandotherfactors.Forsomemures,trafficvolumemaybesolowthatnosurfacingiseconomicallyjustifiedandnaturalsoilservesastheroadway.Astrafficincreases,asurfacingofsandycluy,crushedslag,crushedstonecalichecrushedoystershells,oracombinationofthesemaybeapplied.Ifgravelisused,itusuallycontainssufficientclayandfinematerialtohelpstabilizethesurfacing.Gravelsurfacesmaybefurtherstubilizedbyapplicationofcalciumchloride,whichalsoaidsincontrollingdust.AnothersurfacingiscomposedofPortlandcementandwatermixediutotheupperfewinchesofthesuhgradeandcompactedwithrollers.ThisprocedureformsAsoil-cementbasethatcanbesurfacedwithbituminousmaterials.Roadwaysrocarrylargevolumesofheavyvehiclesmustbecarefullydesignedandmadeofconsiderablethickness.Muchofhighwayengineeringisdevotedtotheplaningandconstructionoffacilitiestodrainthehighwayorstreetandlocarrystreamsacrossthehighwayright-of-way.Removalofsurfacewaterfromtheroadorstreetisknownasurfacedruiuage.Itisaccomplishedbyconstructingtheroadsothatithasacrownandbyslopingtheshouldersandadjacentareassoastocontroltheflowofwatereithertowardexistingnaturaldrainage,suchasopenditches,orintoastormdrainagesystemofcalehbasinsandundergroundpipes.Ifastormdrainagesystemisused,asitwouldbewithcitystreets,thedesignengineermustgiveconsiderationtotherntalareadrainingontothestreet,themaximumrateofrunoffexpected,thedurationofthedesignstorm,theamountofpondingallowableateachcarchbasin,andtheproposedspacingofthecatchbasinsalongthestreet.Fromthisinformationthedesiredcapacityoftheindividualeatehbaxinandthesizeoftheundergroundpipingnetworkurccalculated.Indesigningfacilitiestocarrystreamsunderthehighwaytheengineermustdeterminetheareatobedrainedthemaximumprobableprecipitationoverthedrainagebasin,thehighestexpectedrunoffrare.andthen,using(hitinformation,mustcalculatetherequiredcapacityofllit:drainagestructure.Generallydesignsaremadeadequatetoaccommodatenotonlythelargestfloweverrecordedforthatlocationbutthegreatestdischargethatmightbeexpectedunderthemostadverseconditionsforagivennumberofyears.Factorconsideredincalculatingtheexpectedflowthroughaculvertopeningincludesize,length,andshapeoftheopening,roughnessofthewalls,shapeoftheentranceanddownstreamendoftheconduit,maximumallowableheightofwaterattheentrance,andwaterlevelattheoutletMuchengineeringundconstructionworkhasbeendonetoprovidereststopsalongmajorexpresswayroutestespeciallythenationalsystemofinterstatehighways.Thesefacilitiesmustbecarefullylocatedtopermiteasyandsafeexitandreturnaccesstothehighway.Manyunitshavebeenbuilt^sceniclocationsinforestedareastopermitpicnicgroundsandwalkwaysthroughtheforest.Theserestareasareespeciallybeneficialtotho?edriverstravelinglongdistanceswithfewstops..Thecontrolandreductionofnoisealongbusyroutes,especiallyexpressways,hasbecomeanimportantpartofhighwayengineering.Inmanycommunitieshighwallshavebeenhuiltalongeithersideoftheexpressway.Suchwallscanhecostlytoconstruct,hutcanproveverybeneficial,barrierscanreduceoverallnoiselevelsbyover50%.Constructionoperations.Althoughmuchengineeringandplaningmustbedonepreliminarytoit,theactualconstructionisnormallythecostliestpartofmakinghighwayuudstreetimprovements.Willitheawardofaconstructioncontractfollowingthepreparationofthedetailedplansandspecificationstengineersgoontotheftiteandlayouttheproject.Aspartofthisstakingout.limitsofearthworkareshown,locationofdrainagestructuresindicated,andprofilesestablished.Heavyrollersareusedtocompactthesoilorsubgradebelowtheroadwayinordertoeliminatelatersettlement.Pneumatictiredrollersandsheepsfootrollers(steelcylindersequippedwithnumerousshortsteelteethorfeetJareoftenemployedforthisoperation.Vibratoryrollershavebeendevelopedandusedonsomeprojectsinrecentyears.Onetypevibratesupto3400times/min,compactingtheunderlyingmaterialtoanappreciabledepth.Maintenanceandoperation.Highwaymaintenanceconsistsoftherepairandupkeepofsurfacingandshoulders,bridgesanddrainagefacilities?signs,trafficcontroldevices,guardrails,trafficstripingonthepavement,retainingwalls,andsideslopes.Additionaloperationsincludeicecontrolundsnowremoval,becauseitisvaluabletoknowwhysomehighwaydesignsgivebetterperformanceandprovelesscostlytomaintainthanothers,engineerssupervisingmaintenancecanoffervaluableguidancetodesignengineers.Consequently,maintenanceandoperationarcimportantpartsofhighwayengineering.2、外文資料翻譯譯文路（公路）公路是供汽車或其他車輛行駛的一種線形帶狀結構體。它是由路基、路面、橋梁、涵洞和隧道等基本部分組成。此外，還有路線交叉、防護工程和交通工程及沿線設施等。路基是路面、路肩、邊坡、邊溝等部分的基礎，如下圖所示。它是按照路線的平面位置和設計高程在地面上開挖和填筑成一定斷面形式的線形人工土石料構造物。路基作為行車部分的基礎，必須保證有足夠的強度和穩定性，能防止水及其他自然災害的侵蝕。路面是公路表面部分。它是用一定級配的混合料鋪筑于路基之上的單層或多層結構物。路面要求平整，具有足夠的強度，良好的穩定性和抗滑性能。路面質量的好環，直接影響到行車的安全性、舒適性和車輛的通行能力。路面標線是在高級、次高級路面上用漆類物質噴刷或用混凝土預制塊、瓷瓦等作的一種交通安全設施。它的作用是配合標志牌對交通運輸作有效的管制，指引車輛分道行駛，達到暢通和安全的目的。我國公路路面標線有行車道中線、車道分界線、路緣線、停車線、禁止超車線、導流帶、人行橫道線、交叉路口中心圈、停車方位線、導向箭頭等。路面標線有連續實線、間斷線和箭頭指示線等三種形式，其顏色采用白色或黃色。橋涵是公路跨越河流、山谷、通道等障礙物而架設的結構物。一般用鋼筋混凝土、塊石等材料建造而成。隧道是連接山嶺兩側公路的一條山洞。隧道修筑施工技術復雜，工程造價比一般路面高，但它縮短了兩地間行車距離，提高了公路的技術等級，保證了行車快速安全，從而降低運輸成本。公路防護工程是對路基進行防護和加固，以保證路基的強度和穩定性，從而維持正常的汽車通行和行車安全。交通標志為了保證公路運輸的安全運行，除公路工程和車輛性能所要求的設備和條件外，還必須有交通標志、路面標線等各種指揮、顯示設施。公路標志，是用一定的標記，繪以符號、圖案、簡單文字、號碼等，裝設在適當的地點，預示前方公路的狀況或事故發生的狀態。包括指示標志、警告標志、禁令標志、指路標志等。聯接城市、鄉村和工礦基地之間，主要供汽車行駛并具備一定技術標準和設施共交通之路得名；外國人叫它highway，看來是它建設地基較高，利于行車而來。有人必有路，走的人多勢必成路，這是真理。不過，這路并非公路。若說公路的歷史，公元前三千年，古埃及人為修建金字塔而建設的路，應是世界上最早的公路。次之是大約公元前二千年古巴比倫人的街道，比我們中國公路要早很多。公元前五百年左右，波斯帝國大道貫通了東西方，并連接起通往中國的大道，形成了世界上最早、最長的絲綢之路，這可算是二千五百年前最偉大的公路了。古羅馬帝國的公路曾經顯赫一時，它以羅馬為中心，向四外呈放射形修建了二十九條公路，號稱世界無雙。所以產生了至今人們還常用的外國俗語，“條條道路通羅馬”。公路的修建也有個不斷提高技術和更新建筑材料過程。最早當然是土路，它易建但是也易壞，雨水多些，車馬多此，便凹凸不平甚至毀壞了。歐洲較早出現了碎石路，這比土進了一大進。再后出現了磚塊路，也比中國早很多。在碎石上鋪澆瀝青是公路史上一大突破，這是近代的事了。中國自古有驛站驛路，但是真正第一條較先進的公路，是1906年鋪設的廣西龍州至鎮南關的公路。公路和道路的區別道路是供各種車輛（無軌）和行人通行的工程設施。按其使用特點分為城市道路、公路、廠礦道路、林區道路及鄉村道路等。公路的分類一、按行政等級劃分公路按行政等級可分為：國家公路、省公路、縣公路和鄉公路（簡稱為國、省、鄉道）以及專用公路五個等級。一般把國道和省道稱為干線，縣道和鄉道稱為支線。國道是指具有全國性政治、經濟意義的主要干線公路，包括重要的國際公路，國防公路、連接首都與各省、自治區、直轄市首府的公路，連接各大經濟中心、港站樞紐、商品生產基地和戰略要地的公路。國道中跨省的高速公路由交通部批準的專門機構負責修建、養護和管理。省道是指具有全省（自治區、直轄市）政治、經濟意義，并由省（自治區、直轄市）公路主管部門負責修建、養護和管理的的公路干線。縣道是指具有全縣（縣級市）政治、經濟意義，連接縣城和縣內主要鄉（鎮）、主要商品生產和集散地的公路，以及不屬于國道、省道的縣際間公路。縣道由縣、市公路主管部門負責修建、養護和管理。鄉道是指主要為鄉（鎮）村經濟、文化、行政服務的公路，以及不屬于縣道以上公路的鄉與鄉之間及鄉與外部聯絡的公路。鄉道由人民政府負責修建、養護和管理。專用公路是指專供或主要供廠礦、林區、農場、油田、旅游區、軍事要地等與外部聯系的公路。專用公路由專用單位負責修建、養護和管理。也可委托當地公路部門修建、養護和管理。二、按使用任務、功能和適應的交通量劃分根據我國現行的《公路工程技術標準》（JTJ001-1997），公路按使用任務、功能和適應的交通量分為高速公路、一級公路、二級公路、三級公路、四級公路五個等級：1、高速公路為專供汽車分向分車道行駛并應全部控制出入的多車道公路。四車道高速公路應能適應將各種汽車折合成小客車的年平均日交通量25000～55000輛。六車道高速公路應能適應將各種汽車折合成小客車的年平均日交通量45000～80000輛。八車道高速公路應能適應將各種汽車折合成小客車的年平均日交通量60000～100000輛。2、一級公路為供汽車分向分車道行駛并可根據需要控制出入的多車道公路。四車道一級公路應能適應將各種汽車折合成小客車的年平均日交通量15000～30000輛。六車道一級公路應能適應將各種汽車折合成小客車的年平均日交通量25000～55000輛。3、二級公路為供汽車行駛的雙車道公路。一般能適應每晝夜3000～7500輛中型載重汽車交通量。4、三級公路為主要供汽車行駛的雙車道公路。一般能適應每晝夜1000～4000輛中型載重汽車交通量。5、四級公路為主要供汽車行駛的雙車道或單車道公路。雙車道四級公路能適應每晝夜中型載重汽車交通量1500輛以下。單車道四級公路能適應每晝夜中型載重汽車交通量200輛以下。高速公路工程包括高速公路計劃.選址.設計和高速公路保養。當一項高速公路工程設計建設或是改造之前，必須大致地計劃考慮一下費用問題。作為概要計劃的一部分，該地區在可預見的時段內（如20年）的交通流量，以及何種建設才能滿足這種需求將是決定因素。為了評估交通需求量，高速公路工程師通過采集分析現有設備提供的物理數據信息——包括車流量，分布，現有交通工具的特征以及蘊涵在這些因素中的可以預知的變化。高速公路工程師必須決定新路線建筑最適合的位置.布局以及容量。通常情況下，一條初步的線路或選址和若干備選路線都會被拿來研究。細節方面設計通常在一個更佳的選址確定下來之后才開始。為了選擇最佳路線，需要仔細考慮的問題包括：交通需求，（路線）橫貫的地帶，可通行道路的土地價值以及各種方案的結構開銷的預算。在一些大型項目中，利用了航拍技術的攝影測量法被廣泛用于顯示該地帶的特征，這也是一種最經濟的方法。在那些小型工程中，地面繪圖法已經很完美了。資金方面的考慮決定了一項工程是一次性實施還是是否必須分階段建設，每階段建設等資金到位后才開始。在決定最經濟的實施方案時，工程師通過