Geoscience Reference
In-Depth Information
Fig. 19.1. Links and nodes ofthe MTC network
Transportation (Caltrans). Of these, structural information needed for the application is
available for 1125 bridges. These bridges are classified into 28 engineering categories
following the classification definitions in HAZUS (1999) and are used in the analysis
presentedherein.Furthermore,dataon29804linksand10647nodescomprisingtheSan
Francisco Bay Area highway network was provided by the Metropolitan Transportation
Commission (MTC). Figure 19.1 shows the Bay Area highway network system with the
nodes and links identified. For this system 1120 Transportation Analysis Zones (TAZ)
are specified to determine trip origins and destinations (O-D). Daily traffic demand pro-
file developed by Purvis (1999) is used to assign trips during various hours of the day
with appropriate scaling factors. A vehicle car occupancy factor of 1.4 is recommended
by MTC and is applied in the analysis (Caltrans, 2002). The value of time for users is
assumed to be $12.00/hr as recommended in the California Life Cycle Analysis Model
