SummaryofWebinarQ&AQuestion:Howdoyouaccountforshoppers,doctorappointments,etc.?GuyRousseau:Typicallythereisahomebasedshoppingtrippurpose

Question:HowwelldoesthelanduseandTDMlinkagework?IsthereavalidationprocesssothatitcanbeshownthattheunderlyinglanduseassumedfortheTDMisappropriate?GuyRousseau:Usuallytherewouldbeafeedbackloopfromthelandusemodelfeedingbacktothetraveldemandmodel,viacompositeimpedances,suchascongestedtraveltimes,inordertoproperlyreflectcongestionthroughoutlanduseandtraveldemandforecasts

Question:DoestheHHSizebreakoutHHbyage?(i.e.drivingage?)GuyRousseau:Thetraditional4stepmodelsometimesfailtoaccountforageofthehouseholdmembers(thoughhouseholdsizedoesbreakoutbyincomegroupstypically),yetanactivitybasedmodelwithapopulationsynthesizerallowstotakeintoconsiderationageofthehouseholdmembers

Question:Howdoyousuggestmodelingmilitarybaseswherepopulationandemploymentvariessignificantlyfromtimetotime?GuyRousseau:Aspecialgenerator,combinedwithseasonalityeffects,mightdothetrickhere

Question:Isthereanyguidance/publicationsouttheretogofromadailytraveldemandmodeltoatimeofdaymodel?GuyRousseau:Thediurnaldistributionoftrafficthroughoutthedaywoulddictatetheneedtoswitchtoatimeofdaymodel,sayifyouseetheemergenceofamiddaypeak,thenatimeofdaymodelmaybewarranted

Question:Howdoyouaccountforthedivertedtrips?GuyRousseau:Divertedtripsmaybebestaccountedforwithinatrafficmicrosimulationmodel,orperhapsevenatourbasedmodel,traditionalmodelsaresomewhatlimitedtoproperlyreflecttripdiversion

Question:Isbike/pedpartofthislogitmodel?GuyRousseau:Bike/pedtripsareoftensetasideaftertripgeneration,andnotalwaysassigned,unlessyouhaveagoodbike/pedchoicemodelwithenoughdatatosupportit

Question:Soifyourunascenariowithandwithoutabypass,thenatraditionalmodelisnotthebestwaytoestimatediversionfromtheexistingfacilitytothebypass?GuyRousseau:itdependsuponhowdetailedyournetworkcodingis,butinthecaseofabypass,thetraditionalmodelmightsufficehereinthiscase,dependinguponitsfunctionalclassification

Question:HowdoyouestimatethetravelassociatedwiththeUSGAannualchampionshiptournament?GuyRousseau:specialeventsarenotalwayswellaccountedforinatypicalweekday/workdaymodel,unlessonehasaspecialeventmodelcomponent

Question:Sayatripisnotdirectlyfromworktohome,butinsteadworktoshopthentohome,howdoyoudefinethesekindsoftrips?GuyRousseau:nonhomebased,thenhomebasedother

Question:Doyoucalibratetheintersectionturningmovementvolumes?GuyRousseau:intersectionturningmovementsarenotnecessarilyalwayscalibratedwithinaregionaltraveldemandmodel,buttheyareasapartofatrafficmicrosimulationmodel

Question:IstherealegitimatewaytocalculateVMTandVHTfromTAZtoTAZinamodelwith4000TAZs?GuyRousseau:zonetozonematricesandskimmatrices,combinedwithtraveltimesanddistancesfromzonetozonemayhelpheredeterminewhatyouneed

Question:Howdoyoumodelcollegefootballgamesinthefall?GuyRousseau:hereagain,specialeventswouldneedtobepostprocessedinordertobefactoredin,rememberherewemodelthetypicalweekdayworkday

Question:Iftheintersectionturningmovementvolumesarenotcalibrated,howdowegetthefutureintersectionturningmovementvolumesfromtheforecastingmodel?GuyRousseau:whilewemayobtainintersectingvolumesfromlinkscrossings,leftturnandrightturnandthroughmovementsarebestobtainedinamicrosimulationmodel

Question:Isthereagoodwaytoaccountforsignalsinatraditionalmodel?GuyRousseau:viaturnpenaltiesandturnprohibitionsyoumayaccountfortrafficsignals

Question:TranscadorTransplanwhichisbetter?GaryThomas:FHWAandtheTMIPprogramdonotendorseorcommentonthequalityofvarioussoftwarepackages.

Question:Howarethedifferentattractioncriteriaweighted?Forexamplewhenweighingtransitwiththecriterialistedtheoverallcostwouldbelowerwhereastraveltimemaybehigher.Ultimatelyhowcouldyouusethecriteriatoplanfordifferentmodalbalancingutilizingexistingtraveldata?EricPihl:Generallythoserelationshipsareestablishedwhenmodelsareestimated.Generallychoicebasedmodelsenabletheinclusionofvariablesthatrelatetolandusecharacteristicsandotherimportantattributes,andthoseweightsarederivedusingmodelestimationsoftware(alogitandlimdeparecommonpackages)

Question:Howcanamodelreplicateandevaluatecompletestreetpolicy?EricPihl:Somemodelsinthe90sweredevelopedwith'pedestrianenvironmentfactors'todescribebike/pedfriendlinessandconsideredinnetworkassignment.Otherapproachesmayincludeadjustingthespeedandcapacityinputstomodelsasaproxyfordesignimprovements.

Question:Ifwewouldliketosimulatetheintersectionoperationin2030,weneedtogettheintersectionturningmovementfromtheforecastingmodel,butwejustdon'thavetheaccuratevolumesifnotcalibrated?EricPihl:Turningmovementsareoftendifficulttomatchwithouttheadoptionofturnpenaltiesintripassignment.ManyareasuseNCHRP255methodsthatsimplyfactorcountsbasedonmodelderivedgrowthrates.