Network Development and Zone Definition CE 451/551

Network Development and Zone Definition What factors impact the design of TAZ boundaries? What link attributes are required for network coding? What types of networks are used in TDF? What steps of the TDF process are networks used for?

Centroids, centroid connectors, external stations, links, networks, nodes, zones (TAZs), districts

TAZ definition: consistency, census, network, barriers, homogeneous land use, rule of thumb per population

Centroids no yes Future??? Centroid = center of activity … future? Centroid connectors = representation of roads … future? Future???

Networks used in what steps? Networks used in what steps? Gen? (access); dist/mode/assign Highway, transit, HOV …

Network versions Base year E+C Interim years Adopted Plan Alternatives Time of day Base: calib/valid E+C: TIP

Sample network attributes Nodes: x,y,type,penalty, prohib, delay Links: fnode, tnode, 1way, length, type, lanes, area type, cap, speed, transit route Nodes: x ,y, type, penalty, prohib, delay Links: fnode, tnode, 1way, length, type, lanes, area type, cap, speed, transit route

http://www.caliper.com/PDFs/TravelDemandModelingBrochure.pdf

access links Same zone structure? Implications?

Lookup vs. individual coding; facility type (functional class, define) + area type = speed/cap; define functional classes – give example Area type: CBD, CBD fringe, mixed urban, non-cbd business, sub/res, rural

Selecting network from line file …

Disabling links … why?

Network “skims” Distribution, assignment; output is a matrix of travel time or “skims”

Turn penalties/prohibitors

Route through centroids?