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Application of Three Types of Multi-Point Assignments. Yanping Zhang Durham-Chapel Hill-Carrboro MPO/City of Durham Soon Chung North Carolina DOT Gnani Mahalingam City of Kansas City, MO Mohsin Zaidi Virginia DOT. Finding shortest time paths between centroids
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Application of Three Types of Multi-Point Assignments Yanping Zhang Durham-Chapel Hill-Carrboro MPO/City of Durham Soon Chung North Carolina DOT GnaniMahalingam City of Kansas City, MO MohsinZaidi Virginia DOT 14th TRB Transportation Planning Application Conf. - May 2013
Finding shortest time paths between centroids • Weak control on trip local loading directions 6th St 400 Zone Centroid - Origin 33.3% East Ave Standard User Equilibrium (UE) Assignment West Ave 600 200 Zone Centroid - Destination 33.3% Access Point 200 33.3% 600 Centroid Connector 400 7th St 14th TRB Transportation Planning Application Conf. - May 2013
Finding shortest time paths between access points • Strong control on trip local loading directions 6th St East Ave Zone Centroid - Origin West Ave 300 UE Multi-Point Assignment (MPA) Type 1 - Fixed Loading Rate 25% 600 240 Zone Centroid - Destination 60 40% 10% Access Point 240 60 25% Centroid Connector 600 300 7th St 14th TRB Transportation Planning Application Conf. - May 2013
Type 2 - Fixed/Variable Loading Rates by Centroid Connector 6th St • 40% O-D Trips Loaded onto West Ave • 60% O-D Trips follow UE assignment to other 3 directions, i.e. r1+r2+r3=60% East Ave West Ave 50% r2 40% r1 r3 50% 7th St 14th TRB Transportation Planning Application Conf. - May 2013
Type 3 – Fixed/Variable Loading Rates by Group of Trips 6th St • 60% trips follows the fixed rates • 40% trips follows the UE assignment rule, r1+r1+r3+r4=40% East Ave West Ave 50% 15%+ r2 24% + r3 6% + r1 15% + r4 50% 7th St 14th TRB Transportation Planning Application Conf. - May 2013
Summary of Three MPA Types • Type 1 - Fixed Rate Loading Strategy, Robert Shull 1999 (implemented in TModel2) • Limitations of Fixed Loading Rates. • Not Account for Future Land Use & Accessibility Change • Not Account for special cases , like Partial fixed Loading • Type 2 - Fixed/Variable Rate Loading by centroid connectors • Some centroid connectors got fixed loading rates • Other centroid connectors got the variable rates determined by UE assignment • Type 3 – Fix/Variable Rate Loading by Trip Groups • One Group of trips follows the fixed rate strategy • Another group of trips follows the UE assignment 14th TRB Transportation Planning Application Conf. - May 2013
MPA Tool Multi-Class MPA tool, coded in GISDK for use in TransCAD • MPA (Type) Field in node layer and it can handle MPA value=1, 2, 3 in one model • In/Out rate fields in link layer 14th TRB Transportation Planning Application Conf. - May 2013
Subarea MPA Application 2005 PM Peak Hour - North Land Subarea, Kansas City. The airport & north shopping mall are located in the subarea • MPA Result • Non-MPA Result 14th TRB Transportation Planning Application Conf. - May 2013
Type 2 - Zone with Off-Site Loading • Triangle Regional Model (TRM) V4, 2005 PM Peak Assignment 14th TRB Transportation Planning Application Conf. - May 2013
Types 1 and 3 – Special Zone-RDU Airport • Triangle Regional Model (TRM) V4, 2005 PM Peak Assignment 14th TRB Transportation Planning Application Conf. - May 2013
Conclusions • MPA improves local traffic loading for large special zones, such as airport, university campus, and shopping mall 2. MPA improves traffic loading for off-zone (site) parking lot/garage 3. MPA improves the assignment result for the small area studies and/or the corridor study. 14th TRB Transportation Planning Application Conf. - May 2013