By Rachel Copperman, Cambridge Systematics

The California High-Speed Rail project is a future high-speed train network being planned by the California High-Speed Rail Authority (CHSRA). The objective of the California High-Speed rail system is to link major metropolitan areas of the state using a fast, reliable, safe, efficient, convenient, and economical mode of transportation.

When built, high-speed trains traveling at 220 mph will link San Francisco and Los Angeles in as little as two hours and forty minutes. The planned system will also serve other major California cities, including Sacramento, San Jose, Fresno, and San Diego. The plan is to serve 90 percent of the state’s population (CHRSA, 2008). Figure 1 shows the approximate alignment for the high-speed rail system.


Figure 1: California High-Speed Rail Alignment and Stations

In November, 2008, California voters passed Proposition 1A, authorizing $9.95 billion in general obligation bonds for the project. $9 billion will go directly toward constructing the first phase of the high speed rail system between San Francisco and Los Angeles, and the other $950 million will be spent on improvements to existing commuter, intercity rail and transit lines connecting existing infrastructure to the high speed rail network. The project will also rely on other sources of funding including Federal and local government and private companies (CHRSA, 2008).

Development of Statewide Travel Model
In 2005, the Metropolitan Transportation Commission (MTC) for the San Francisco Bay Area and the CHSRA retained Cambridge Systematics to develop an innovative statewide model to support evaluation of high-speed rail alternatives in California. The approach to this statewide model explicitly recognized the unique characteristics of and differences between interregional and intraregional travel demand.

Interregional travel models capture behavior important to longer-distance travel, such as induced trips, business and commute decisions, recreational travel, attributes of destinations, reliability of travel, party size, and access and egress modal options.

Intraregional travel models rely on local highway and transit characteristics and behavior associated with shorter-distance trips (such as commuting and shopping). The core model design feature recognized that interregional and intraregional travel characteristics should be modeled separately to accurately capture these distinctions.

The integrated modeling process is presented in Figure 2. The accessibility of the high-speed rail system is included in the mode choice models for both the intraregional, or urban, and interregional models, and in the trip frequency and destination choice models for the interregional model. This feature allows the estimation of induced travel for the interregional travel market. For intraregional models, only the mode choice models are sensitive to level-of service; all other portions of the model are held constant for a given horizon year. For this reason, intraregional trip generation and trip distribution are kept outside of the context of the California Statewide Model for High-Speed Rail. Instead, trip tables for the forecast year are obtained from the appropriate MPOs and input to the high-speed rail model.

Four sets of models comprise the interregional models: trip frequency, destination choice, main mode choice, and access/egress mode choice. Intraregional and interregional trip tables are combined prior to trip assignment.

The California Statewide Model for High-Speed Rail has been implemented using the Cube Voyager software system. The intraregional model components are run completely within Cube Voyager. The interregional model components of trip frequency, destination choice, and mode choice are run using a separate executable program written using the Python programming language. However, the program is called directly from Cube Voyager and directly inputs station access, station egress and station-to-station skims by mode developed using Cube Voyager. In addition, trip tables output from the interregional model are used by the Cube scripts for trip assignment.


Figure 2: Integrated Modeling Process

Cube Interface Procedures
Application Manager of Cube Base is used extensively to organize, manage, and implement the California Statewide Model for High-Speed Rail. Given that the Statewide Model is very large and complex, it is not always desirable or necessary to run the entire model. The hierarchical flow chart design has made it very easy to start the program at any point in the system, or run only a portion of the model. Figure 3 shows the highest level of the flow chart. The interregional model and intraregional models are run independently and output from the model systems are fed into trip assignment and model output summary procedures.

The California Statewide Model for High-Speed Rail has been used to evaluate high-speed rail ridership and revenue on a statewide basis for different planning years and for various scenarios. The model has been tested and validated for the 2000 base year and used to forecast high-speed rail ridership for 2030. The scenarios examined include operational plan changes such as alternative alignments, service frequencies, and station locations, and other level of service (LOS) assumptions including changes to fare policies and operating costs.

Figure 3: California Statewide Model for High-Speed Rail with Cube Base

Cube’s Scenario Manager has provided a convenient interface for managing and implementing the various scenarios. When a new scenario is created, Cube Base automatically creates a folder within the pre-defined sub-directory, ensuring that all input and output files for the scenario are placed in the correct location. In addition, the model has been designed to make use of the “Keys” feature within Cube Base.

Keys provides an easy method for changing model inputs such as number of zones, file paths, and fuel and parking costs. When a Key’s value is changed, all scripts that access the value are automatically updated with the new value. Other input files, such as high-speed rail line files or air and conventional rail fare matrices, may require manual alterations. However, the Scenario Manager file organization system and the convenient interface for viewing and editing data using Application Manager, make changes straightforward and easy to ensure that the correct file is being used for each scenario.

Reference: California High Speed Rail Authority, California High-Speed Train Business Plan, November 2008.