Designation:E2176–08StandardTestMethodforMeasuringtheCoefficientofRetroreflectedLuminanceofPavementMarkingsinaStandardConditionofContinuousWetting(RL-Rain)1ThisstandardisissuedunderthefixeddesignationE2176;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversameasurementofthewetretroreflective(RL-Rain)propertiesofhorizontalpavementmarkingmaterials,suchastrafficstripesandroadsurfacesymbols.1.2Thismethodofmeasuringwetretroreflectiveproperties(RL)ofpavementmarkingsutilizesamethodofcontinuouslywettingthemarkingduringmeasurement(seeFig.1).NOTE1—TestMethodE2177maybeusedtodescribetheretroreflec-tivepropertiesofpavementmarkingsinconditionsofwetnessafteraperiodofrain.1.3Thistestmethodismostsuitableforlaboratoryuseundercontrolledconditions,butmayalsobeusedforfieldmeasurementswhenthenecessarycontrolsandprecautionsarefollowed.1.4ThistestmethodspecifiestheuseofreflectometersthatcanmeasurepavementmarkingsperTestMethodE1710.2Theentranceandobservationanglesrequiredoftheretroreflecto-meterinthistestmethodarecommonlyreferredtoas“30metergeometry.”21.5Thistestmethodhasbeenshowntoproducereasonableresultsforpavementmarkingsystemswithopticshavinganindexofrefractiongreaterthan2.0andstructuredmarkingshavingverticalstructuresgreaterthanorequalto3mm.3Usersshouldexercisecautionwhenusingthistestmethodforpavementmarkingsystemswithopticshavinganindexofrefractionlessthan2.0ormarkingshavingverticalstructureslessthan3mm.1.6Resultsobtainedusingthistestmethodshouldnotbethesolebasisforspecifyingandassessingthewetretroreflectiveeffectivenessofpavementmarkingsystems.Usersshouldcomplementtheresultsofthistestmethodwithotherevalua-tionresults,suchasnighttimevisualinspections.1.7Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itisthere...
