Designation:F457−04(Reapproved2010)StandardTestMethodforSpeedandDistanceCalibrationofFifthWheelEquippedWithEitherAnalogorDigitalInstrumentation1ThisstandardisissuedunderthefixeddesignationF457;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofvehiclespeedandcumulativedistancetraveledusingadevicetermedafifthwheelandusingappropriateassociatedinstrumentation.1.2Thistestmethodalsodescribesthecalibrationtechniqueapplicabletodigitaloranalogspeedanddistancemeasurementsystemsemployingafifthwheel.1.3ThevaluesstatedinSI(millimetre-kilogram)unitsaretoberegardedasthestandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Forspecificprecautionarystatements,seeSection7.2.ReferencedDocuments2.1ASTMStandards:2F538TerminologyRelatingtotheCharacteristicsandPer-formanceofTiresF1082PracticeforTires—DeterminingPrecisionforTestMethodStandards(Withdrawn2005)33.Terminology3.1RefertoTerminologyF538.4.SummaryofTestMethod4.1Vehiclespeedanddistancedeterminationsaremadebyuseofafifthwheel,signaltransducer(s),andcompatibledisplaydevices.4.2Thefifthwheelassemblyandsignaltransducer(s)areattachedtothevehicleorthetesttrailersothatthefifthwheelremainsincontactwiththenormalroadwaysurfacewhiletheequipmentisinmotion.Therotationofthiswheelisdetectedinasuitablemannerandistranslatedintomeasurementsofvehiclespeedanddistancewithauxiliaryequipment.4.3Thespeedistobecommunicatedtothevehicleoperatoratalltimes,andshouldbevisiblewithoutunduedistractionorarequirementforphysicalmovementonthepartoftheoperator.4.4Fifthwheelcalibrationisperformedbyoperatingthedeviceatafixed...
