NETS News

Vol II, Issue 4  April 2006

Transportation Demands in the Columbia-Snake River Basin
NETS Researchers Kenneth Train, PhD, of the University of California, Berkeley, and Wesley W. Wilson, PhD, of the Institute for Water Resources and the University of Oregon, continue a stream of research dedicated towards the estimation of transportation demands. This study addresses directly the trade-off between stated-preference data, which provide greater variance in rates and times, useful for estimation and forecasting, and responses in real-world settings. This current study utilizes stated-preference questions that can be expected to be more realistic for shippers, and hence more likely to provide reliable information relative to standard stated-preference methods. The new econometric method combines each shipper’s choices in real-world settings with their responses to the new stated-preference questions. The data for the study were collected through a survey of shippers in the Columbia-Snake River Valley, implemented by the Social and Economic Sciences Research Center at Washington State University.

Fact Sheet | Paper (pdf, 368KB)

2006 Journal of the Transportation Research Board to Publish NETS Researchers
NETS Researchers Drs. Kenneth Train and Wesley Wilson wrote two papers to be published in the upcoming 2006 Journal of the Transportation Research Board.  “Spatial Demand Decisions in the Pacific Northwest: Mode Choices and Market Areas”, written by both researchers, reports the results of a survey of shippers located on and off the Columbia-Snake waterway in the Pacific Northwest to estimate shipper level demand decisions. The model addresses the concerns about the current USACE planning models by estimating elasticities rather than assuming them and by allowing the probability of using the river to be explained in terms of the spatial setting of the demander. The survey provides choices (rate, transit times and reliability) made in both revealed and stated preference settings, combining the data to estimate demand functions. The simulation suggests that as distance from the waterway increases, the likelihood of using the waterway falls.

The second paper, “Vessel, Firm and Lock Efficiency Measures in Lock Performance,” written by Dr. Wilson, examines lock performance in terms of the structural design of locks, the characteristics of the flotilla (vessels and barges), a set of state conditions (weather, river levels, etc.), and characteristics of vessels, lock and firms.  Vessel, firm and lock efficiency measures are developed using panel data techniques, and observed factors that influence efficiency are evaluated. The results point to considerable heterogeneity across vessels, firms, and locks that result in significant differences in timely passage through the locks.

Columbia Snake Transportation Demands
Fact Sheet | Paper (pdf, 73KB)
Lock Performance
Fact Sheet | Paper (pdf, 447KB)
Transportation Research Record: Journal of the Transportation Research Board

HarborSym Model Presented at Mexico Seminar
Dr. Richard Males of RMM Technical Services, Inc. presented Data-Driven Monte Carlo Simulation Models for Engineering-Economic Analysis at the recent Seminar on Water Resources Management in Merida, Yucatan, Mexico, March 12-15, 2006. The seminar was a joint meeting of U.S. and Mexican government and university researchers and officials, with various presentations on water resource problems in Yucatan, as well as planning and environmental applications in the U.S. The presentation discussed both HarborSym and BeachFx.

Fact Sheet | Presentation (ppt, 5.63MB)

Genetic Algorithm Optimization Enhancements Made by NaSS Team Members
Navigation System Simulation Model (NaSS) researchers Paul Schonfeld, PhD, and Shiaaulir Wang, both of the University of Maryland, recently completed work on adding important enhancements to the genetic algorithm optimization process.  The optimization process now contains the ability to account for construction impacts, such as reduced capacity over a construction period that may take several years.  Also, the process can now select from among multiple mutually exclusive candidates at several project sites. This work provides a promising demonstration of simulation-based optimization.

Fact SheetPaper (pdf, 484KB)


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