Travel Demand Model - OKI

OKI/MVRPC Travel Demand Model – Version 6.0The highway network definition is contained in five separate files (see descriptions below). Link,node and turn prohibition files were developed for the consolidated system network byreformatting and merging the respective files from the existing OKI and MVRPC networks. Thesefiles were named with extension .95C, indicating that they represent the 1995 consolidatednetwork. Specific changes made to these files are detailed in Sections 3.1 and 3.2.• N0009: link file• N0008: node file• Turnpen: turn penalties• Turnpro: turn prohibitions• Bridge: major bridges3.1 OKI Highway NetworkThe OKI 1995 base network was taken "as-is", with the following link and centroid changes:• New centroids and centroid connectors were added to represent all the zones added by OKIin excess of their original zone system (approximately 600 new centroids were required);• New centroids and centroid connectors were added to represent cordon stations surveyed bythe Ohio Department of Transportation but not originally included in the 1995 zone system(see Appendix B);• The Ohio County (IN) highway network was eliminated from the consolidated network;• All highway node numbers were renumbered, by adding 1800 to the original number, toaccommodate the additional OKI centroids and MVRPC TAZs.• Bridge and TurnPro files were updated to reflect the new node numbering system.• Two new attributes were added: REGION, to indicate whether a link falls in the OKI orMVRPC area, and TRUCKPROH, to flag links on which truck traffic is not allowed.3.2 MVRPC Highway NetworksMVRPC network attributes were edited to ensure consistency with the OKI attribute definition(see Table 3-1). The new attributes include a speed/capacity code and revised facility type andadministrative class definitions. These codes are used to calculate link capacities, using theinformation shown in Table 3-2: for each link, capacity is assigned as a function of thespeed/capacity code and the administrative class code. Note that all capacities are calculated forlevel of service E and that no adjustments are made to reflect the effect of truck volumes.Free-flow speeds were set equal to the posted speed limit. Some OKI network attributes are notavailable in the MVRPC networks, but as they are not used in the current model version it wasnot necessary to collect and/or code this information (see Table 3-2).Highway network node numbers were shifted by 12,000 in Montgomery and Greene counties andby 19,000 in Miami County. All centroids and external stations were renumbered according tothe consolidated zone system numbering.Zones and Networks / 3 - Highway Network Consolidation6