I-66 Multimodal Study Final Report - Virginia Department of ...

Multimodal PackagesMeasures of EffectivenessPerformance measures or measures of effectiveness, which were generated for each of themobility options, were produced for each package as well as some additional measures. As inthe options analysis, these measures help assess how well packages address issues and needsand the study goals. Emphasis was on the following parameters, which are outputs from thetravel demand forecasting model:Vehicle Miles of Travel (VMT) – VMT quantifies the amount of travel by motorizedvehicles in the study area. VMT was calculated in the study area during the morning andevening peak periods and divided into three categories based on congestion levels: uncongested,near capacity, and over capacity. The division into these categories was based onvolume to capacity ratios. Preferred are packages that reduce congested VMT in the studyarea, both in quantity and percentage.Person Miles of Travel (PMT) – PMT quantifies the amount of travel by people in thestudy area, and does include travel on transit, although nonmotorized travel is notincluded. Daily PMT was calculated for three facility types in the study area: rail, freeways,and arterials. The PMT numbers for freeways and arterials include travel by buspassengers on those facilities as well as automobile drivers and passengers. Preferred arepackages that increase PMT in the study area, especially packages in which the PMTincreases more than the VMT. This condition indicates packages which have higher use oftransit and other shared ride modes.Non-SOV Mode Share – Daily mode shares were calculated for all trip purposes starting orending in the study area. Focus was given to the commuting trips from home to work andfrom work to home. This trip purpose contributes to the majority of transit trips. Thesetrips tend to be longer than other trip purposes and have greater impact on the network.They are defined in the model as Home-Based Work (HBW) trips. Preferred are packagesthat increase the HBW share of non-SOV travel (Transit, HOV 2, and HOV 3+) in the studyarea. For the multimodal packages, the mode share was also calculated for all trip purposescombined.Person Throughput – Person throughput is calculated as the number of people crossing acutline by rail, bus, or auto daily, in either direction. This measure was evaluated at fourcutlines along the corridor, (shown in Section 2.0, Figure 2.2). Preferred are packages thatincrease person throughput.Travel Time – Travel time differences within the corridor were calculated for highway (brokenout by SOV and HOV) and for transit. The travel times were calculated for thefollowing select origin and destination pairs: Rosslyn, Ballston, and the D.C. core,Pentagon, Seven Corners, Tysons Corner, Reston, Manassas, Merrifield, and the City ofFairfax. Changes reflect improved (or degraded) mobility and accessibility only within thecorridor, including improved (or degraded) connections to activity centers that are locatedin or near the study area. This comparison does not include changes in travel times beyondthe study area.I-66 Multimodal Study 3-7