1Sussman’s Key PointsAs relayed byDavid LevinsonPeople andorganizations alterbehavior based ontransportation systemexpectations.Transportationservice is part of abroader system -economic, social, andpolitical in nature.Competition, or itsabsence, for customersby operators is acritical determinant ofthe availability ofquality transportationservice.Analyzing the flow ofvehicles ontransportationnetworks, and definingand measuring theircycle is a basicelement oftransportationsystems analysis.Queueing for serviceand customers andstorage forvehicles/freight/travelers are fundamentalelements oftransportationsystems2Intermodal andintramodal transfersare key determinantsof service quality andcost.Operating policyaffects level ofserviceCapacity is a complexsystem characteristicsaffected by:infrastructure, vehicles,technology, labor,institutional factors,operating policy,external factors (e.g.clean air, safety,regulation).Level of service =f(volume);transportation supply.As volume approachescapacity, level of servicedeterioratesdramatically - the"hockey stick"phenomenon.The availability ofinformation (or thelack thereof) drivessystem operations andinvestment andcustomer choicesThe shape oftransportationinfrastructureimpacts the fabric ofgeo-economicstructures.3The cost of providing aspecific service, theprice charged for thatservice, and the level-of-service providedmay not beconsistent.The computation ofcost for providingspecific services iscomplex, and oftenambiguous.Cost level of servicetradeoffs are afundamental tensionfor the transportationprovider and thetransportationcustomer, as well asbetween them.Consolidation of likedemands is often usedas a cost minimizingstrategy.Investments incapacity are oftenlumpy (e.g.infrastructure).The linkages betweenCapacity, Cost, andLevel of Service - thelumpiness of investmentjuxtaposed with the hockeystick level of servicefunction as volumeapproaches capacity - is thecentral challenge oftransportation systemsdesign.4Temporal peaking indemand: a fundamentalissue is design capacity- how often do we notsatisfy demand.Volume = f(level ofservice);transportationdemand.Level of service isusuallymultidimensional.For analysis purposes,we often need toreduce it to a singledimension, which wecall utility.Different transportationsystem components andrelevant externalsystems operate andchange at differenttime scales (e.g. shortrun - operating policy;medium run - autoownership; long runinfrastructure, land use).Equilibration ofsupply and demand fortransportation serviceto predict volume is afundamental networkanalysis methodology.Pricing oftransportation servicesto entice differentbehavior is a mechanismfor lowering thenegative externalitiescaused by transportationusers on othertransportation usersand society-at-large.5Geographical andtemporal imbalancesof flow arecharacteristic intransportationsystems.Network behaviorand networkcapacity, derived fromlink and nodecapacities andreadjustment of flowson redundant paths,are important elementsin transportationsystems analysis.Stochasticity insupply and demand ischaracteristics oftransportationsystems.The relationship amongtransportation,economicdevelopment, andlocation ofactivities - thetransportation/landuse connection - isfundamental.PerformanceMeasures shapetransportationoperations andinvestment.Balancingcentralized controlwith decisions madeby managers ofsystem components (e.g.terminals) is animportant operatingchallenge.6The Integrality ofvehicle/infrastructure/controlsystems investment,design, and operatingdecisions is basic totransportation