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A C T I V I T Y- B A S E D M O D E L S 31 RECENT DEVELOPMENTS WITH THE PRISM- ods for each individual. It incorporates modal con- CONSTRAINED ACTIVITY-TRAVEL SIMULATOR straints related to availability, speed, and captivity. AND INTEGRATION WITH THE DYNAMIC The structure of PCATS is a series of models to sim- EVENT-BASED NETWORK SIMULATOR ulate activity-travel patterns. These models include activity-type choice models, joint destinationmode choice Ram Pendyala, Ryuichi Kitamura, and models, and split population survival models of activity Kaira Kikuchi duration. There are also models by market segment focus- ing on workers, nonworkers, students, and other groups. Ram Pendyala discussed recent developments with the The origindestination matrix creator aggregates activity- Prism-Constrained Activity-Travel Simulator (PCATS) travel records to create origindestination matrices by pur- and the integration of PCATS with the Dynamic Event- pose, mode, and time of day. It can also be imported into Based Network Simulator (DEBNetS). He summarized any traffic assignment program. the background to the development of PCATS, recent There are a number of recent developments related efforts, and future activities. The following points were to these models and technical tools. One of the major covered in his presentation. efforts focused on developing an interface and integra- tion with UrbanSim into the OPUS platform. The effort There has been rapid progress in activity-based represents a major enterprise. PCATS is also being model development over the past decade. The Activity refined to incorporate quasi-continuous representation Mobility Simulator (AMOS) was developed with ini- of the timespace domain. The model's interactions tial funding from the Travel Model Improvement Pro- among household members are also being enhanced. The gram. Components of AMOS include Household integration with DEBNetS is focusing on enhancing the Attributes Generation System (HAGS), PCATS, and visualization capabilities. There are also plans to inte- DEBNetS. In addition, the Florida Activity Mobility grate a pedestrian movement simulator. Simulator (FAMOS) is the Florida application of The dynamic network simulator considers activi- AMOS. It represents the calibration of HAGS and ties and trips as events that occur in the timespace PCATS using Florida data. It was tested using area domain. DEBNetS loads events on the multimodal net- data and networks from southeast Florida. It was work and dynamically updates paths based on network funded by the Florida Department of Transportation conditions. Standard speedflow relationships are used and completed in 2004. to compute speeds and travel times. Enhancements to AMOS includes the household travel survey data, the visual displays and animations capabilities are the zonal socioeconomic data, and the network LOS underway. data. All of these data feed into HAGS. HAGS generates Integrating PCATS, DEBNetS, and UrbanSim repre- a synthetic population of households and persons. All of sents an innovative approach in land use and transporta- the elements feed into PCATS, which in turn generates tion modeling. The OPUS initiative is an international detailed activity-travel records for each person. There is collaboration initiated by Paul Waddell at the University also an output processor, which generates origindesti- of Washington. It will interface UrbanSim with a host of nation matrices by trip purpose, time of day, and mode. model systems and analytical and visualization tools. A new feature is DEBNetS. OPUS will create an integrated open source platform with HAGS populates each zone with a synthetic popu- land use and urban systems simulation; activity-based lation of households and persons based on marginal and travel models; population, demographic, and economic joint distribution determined by survey data and census simulators; and visualization and spatial analysis tools. data. There are two components to HAGS. One compo- These activities focus on linking land use and trans- nent is the household distributor that provides the house- portation and the use of activity-based measures of hold distributions and attributes. The second component accessibility. Activity-based modeling opens new oppor- is the fixed-activity generator. This component deter- tunities to integrate long-, medium-, and short-term mines mandatory activities fixed in time and space for choices related to residence, work, and school locations, each individual. It simulates beginning and ending times as well as vehicle ownership and fixed and discretionary of timespace prisms and of fixed activities. There are activity engagement. It also includes destination accessi- also multinominal logit models of work and school loca- bility accounting for time, cost, and reliability. The tion choice. higher spatial resolution provides improved representa- PCATS is a system of behavioral models that simu- tion of nonmotorized accessibility. late an individual's daily activity-travel patterns. The Work is under way in Japan to introduce a output consists of a series of activity-travel records for microspatial coordinate system into PCATS. The capa- each individual. PCATS defines open and blocked peri- bility to analyze and microsimulate pedestrian move-