Panel finds flaws in high-speed-rail forecasts

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Palo Alto Online reports Panel finds flaws in high-speed-rail forecasts:


Panel finds flaws in high-speed-rail forecasts
Peer-review group calls for changes in California rail authority's ridership model

by Gennady Sheyner
Palo Alto Weekly Staff

The California agency charged with building America's first high-speed-rail system has been using a flawed forecasting model to predict ridership for the proposed system, a peer-review panel concluded in a report that largely confirms previous criticism from transportation experts and rail watchdogs.

The five-member panel, which consists of professors and transportation experts, found that the ridership model, while "generally well founded and implemented," suffers from a series of major flaws. These include insufficient consideration of socioeconomic factors; a bias in the survey data used as a basis for the model; and a failure to distinguish between short and long trips when calculating the impact of schedule delays.

The highly technical report, which was released in late July and covers the panel's findings and recommendations during its January to March review period, confirms earlier findings from the UC Berkeley Institute of Transportation Studies and from the Palo Alto-based watchdog group Californians Advocating Responsible Rail Design (CARRD). Both groups had criticized the methodology used by the consulting firm Cambridge Systematics and argued that the California High-Speed Rail Authority's estimates of the number of people who would ride the rail system are too flawed to be used for setting policy.

The panel, which reports to rail authority CEO Roelof Van Ark, is chaired by Frank Koppelman, professor emeritus of civil engineering at Northwestern University. It also includes Kay W. Axhausen, a professor at the Institute for Transport Planning and Systems in Zurich, Switzerland; Billy Charlton from the San Francisco County Transportation Authority; Eric Miller, a professor of civil engineering at the University of Toronto; and Kenneth A. Small, a professor emeritus in economics at University of California, Irvine.

The panel calls Cambridge's ridership model "ambitious" and representing a "significant improvement in practice in several respects." But the report also notes that "there are important technical deficiencies in the model and the documentation thereof." It encourages the rail authority to lower its projections.

"The Panel has significant concerns about the model formulation, primarily with respect to specification that should have been addressed during previous work," the report states. "Pending improvements to the model, we recommend that any use of the model include some steps to make the demand forecasts more conservative, especially in forecasts for financial (investment and risk) analysis."

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This is the right set of people to review the forecasts. The recommendation to the rail authority lower its projections is the critical one. The forecasts were unfortunately not conducted in a technically objective or neutral way. Lowering the forecasts however might result in a different outcome in an objective B/C analysis. Let's see whether that comes to pass.

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It really seems like flight traffic forecasting (reasonably accurate) should be used for these HSR links. Let's see... a flight with 1,000 seats that is half as fast, with sunk cost of $10 billion plus... what's the expected profitability... given today's market demand... commercial air models could answer that.

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This page contains a single entry by David Levinson published on August 2, 2011 4:25 PM.

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