Roadwaysandtheirgeometric道路基本特路網(wǎng)密道路結(jié)道路線道路網(wǎng)布公路網(wǎng)布局形放射形路三角形路并列形路樹叉形路城市路網(wǎng)布棋盤帶放射放射環(huán)蘭州路東京的路新加坡的路Mobilityand機(jī)動(dòng)性和可達(dá)Mobilityreferstothethroughmovementofpeople,goods,andvehiclesfromPointAtoPointBAccessibilityreferstothedirectconnectiontoabuttinglandsandlandusesprovidedbyroadwaysConceptsofmobilityand機(jī)動(dòng)性和可道路分類分 ongeometricdesignofhighwaysandstreets,2001（Greenbook）城市道路設(shè)計(jì)規(guī)范，CJJ37-HierarchyofroadwayHighwayway(LimitedaccessProviding100%throughNodirectaccesstoabuttinglandusesisSurfacefacilitiesforthroughButpermitsomeaccesstoabuttingIntermediatecategory way,arterialslocalSomemeasureofbothmobilityandaccessLocalAccesstoabuttinglandTypicalruralandurbanroadway

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其國(guó)省國(guó)省縣鄉(xiāng)公城市道路城市道路交通規(guī)劃設(shè)計(jì)支小區(qū) HighwaydesignHorizontalalignment（平面線形Verticalalignment（縱斷面線形Cross-sectionalelements（橫斷面公路設(shè)RogerL公路選線、 設(shè)路基路橋涵洞交通安全設(shè)施、標(biāo)志擋土聲屏HorizontalRefersto nviewofIncludestangentsectionsandthehorizontalcurvesandothertransitionHighwaydesignisgeneratedinitiatedbylayoutasetoftangentsontopographicalanddevelopmentmapsoftheserviceareaConsiderationinselectingForecastdemandvolumes,withknown-orprojectedorigin-destinationpatternsPatternsofNaturalSubsurfaceDrainageEconomicEnvironmentalSocialSurveyingandRoutesurveyorsdefinethegeometryofahighwaybystakingoutthehorizontalandverticalpositionoftheCriticalcharacteristicsofcircularhorizontalcurvesP.I.pointofP.C.pointofP.T.pointofTlengthofEexternalMmiddleordinateL.C.Long?externalangleofRradiusofSuperelevationofhorizontal12%is umsuperelevationinWhensnowandiceareprevalent,aumvalueof8%isusedInurbanareas,speedsmaybereduced umvalue4%-6%Lowspeedurbanstreetsoratintersections,superelevationcouldbeDesignvalueofside-frictionWetpavementsandtiresinreasonablebutnottop DeterminingdesignvaluesofR＝minimumradiusofcurvature,metersS=speed,km/hf=coefficientofsidefrictione=superelevation,expressedasdecimalAchievingTangentSpiraltransitionAspiraltransitioncurvebeginswithatangentandgraduallyanduniformlyincreasethedegreeofcurvatureuntiltheintendedcirculardegreeofcurveisVirtualimpactofspiraltransition?SightdistanceonhorizontalMinimumsightdistanceequalstothesafe distancemustbeprovidedateverypointalongtheroadwaySightdistanceismeasuredalongthearcoftheroadway,usingthecenterlineoftheinsidetravellaneMAminimumPageVerticalThedesignoffacilityintheprofileIncludesgradesandverticalSuretoAdequatesightdistanceatallAdequateMaintenanceofcomfortableMaintenanceofreasonableVerticalAreintheshapeofProvidesanaturaltransitionfromatangenttoacurvedsectionaspartofthecurvecharacteristicsGrade,thelongitudinalslopeofaumum CrawlingCrestverticalcurvesandsagvertical凸形豎曲線、凹形豎SightdistanceonverticalForcrestcurves,thedaylightsightcontrolstheminimumlengthofverticalForsagcurves,theheadlamprangeduringnighttimedrivingcontrolsMeasuredfromanassumedeyeheight3.5ft(1.1m)andanobjectheightof2.0SightdistanceforcrestSightdistanceforsagDesignguidelinesforverticalAsmoothgradelinewithgradualchangesispreferredtoalinewithnumerousbreaksandshortProfilesshouldavoidtheroller-coasterappearance,aswellashiddendipsinthealignmentUndulatinggradelinesinvolvingsubstantiallengthofmomentum(down)gradesshouldbecarefullyevaluatedwithrespecttooperationoftrucksBroken-backgradelines(two-consecutiveverticalcurvesinthesamedirectionseparatedbyashortsection)shouldbeavoidedwhereverpossible八達(dá)嶺高 方向潭峪溝隧翟忠民 DesignguidelinesforverticalcurvesOnlonggrades,itmaybepreferableto cethesteepestgradesatthebottom,lighteningthegradeontheascent.Ifthisisdifficult,shortsectionsoflightergradesshouldbeinsertedperiodicallytoaidWhereat-gradeintersectionsoccuronroadwaysectionswithmoderatetosteepgrades,thegradeshouldbereducedorflattenedthroughtheintersectionareaSagverticalcurvesincutsshouldbeavoidedunlessadequatedrainageisprovidedCross