Travel Demand Model - OKI

OKI/MVRPC Travel Demand Model – Version 6.02.2 Time of Day Factoring and PA to OD Format ConversionTime of day factoring is the process of allocating daily trips (by purpose and mode) into the timeperiods used for highway assignment. The allocation is achieved via use of time of day or diurnalfactors.A time of day factor gives the proportion of total trips (by purpose) that are in-motion during acertain period of the day. These factors are typically developed separately for the production toattraction direction of travel (P-to-A) and the attraction to production direction of travel (A-to-P).This consideration is necessary to ensure that the trips loaded to the networks are in Origin-Destination format, and not in the Production-Attraction format used in all previous modelingsteps.The consolidated model uses the time of day factors developed for Model v54. While the MVRPChousehold survey data include the time at which trips were taken, the information is notsufficiently detailed to develop trip-in-motion factors at 30-minute intervals, the minimumrequirements of the OKI model.Model v54 diurnal factors are structured by direction, hence the PA to OD conversion occurssimultaneously as the time of day factoring. These factors are applied to HBW, HBO, HBU andNHB trips, after they have been augmented with the airport and King's Island trips. Figure 2.1shows the diurnal factors.Figure 2-1 OKI Model v54 Diurnal Factors, Auto Trips20%Trip Proportion15%10%5%0%0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00Time of DayHBW HBO NHB HBUAssignment and Validation - Time of Day and Vehicle Occupancy Factoring 3