Statewide and Megaregional Travel Forecasting Models: Freight and Passenger (2017) / Chapter Skim
Currently Skimming:
Pages 57-68
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 57... ...
58 There is broad consensus on best practices for trip-based travel models in urban areas, and an abundance of literature to inform the development. Activity-based person travel models likewise tend to have similar components, with choices arranged in comparable order, despite their continuing evolution.
|
From page 58... ...
59 Early statewide models tackled the issue of conflicting resolutions by modeling the entire system at the highest level of resolution required for any of its components. Such an approach makes sense when only modeling travel choices.
|
From page 59... ...
60 North America to represent the rest of the continent makes summarization of these data simple. Comparable data are not available for long-distance person travel, except for the small amount of NHTS long-distance data coded to the Census region level.
|
From page 60... ...
61 trip-based freight models as well. Many of these models are created with transferred or synthetic data, as revealed in Figure 44.
|
From page 61... ...
62 fielded surveys designed to capture adequate samples in different regions of the state. The existing model can be updated using these data, or extended with new features or greater detail.
|
From page 62... ...
63 There are about two dozen operational activity-based models across North America, with a halfdozen more known to be under active development. The San Diego model was transplanted to the Miami region, at the cost of about $1 million.
|
From page 63... ...
64 explanatory variables, or capture of non-freight commercial vehicle travel. Hunt & Stefan (2007)
|
From page 64... ...
65 TABLE 5 COMMON ENHANCEMENTS TO TRIP-BASED MODELS Model Enhancement Additional Data Required Estimated Cost Implement base model based upon synthetic or borrowed parameters and updated network information None $50,000 to $250,000, depending upon desired features, level of detail, and other design issues Update or improve existing model Statewide household travel survey $1.5–8.5M, depending upon survey design and sample size Add mode choice models capable of addressing traveler responses to pricing Statewide household travel survey or adaptation of existing urban surveys, possibly augmented with RP/SP survey Costs shown above for travel survey, plus $150,000 to $300,000 for model development, and $500,000 for RP/SP survey Implement destination choice model LEHD data and analyses $50,000 to $100,000 Implement destination choice and visitor models based upon cellular tracking data Third-party cellular tracking data (e.g., AirSage, StreetLight) $250,000 to $2M, depending upon type and resolution of data specified, subscription terms, etc.
|
From page 65... ...
66 and sharing required to improve the practice of freight modeling, although there are several competing proposals. A national freight model, if it were to come to fruition, would also dramatically change the freight modeling landscape, as well as substantially reduce the cost.
|
From page 66... ...
67 are consumed in model estimation and calibration, leaving few available for validation. This is even more true for commercial vehicles, whose underlying business and travel patterns have much wider variances associated with them.
|
From page 67... ...
68 are also widely used to test model performance. Comparisons of average auto occupancy were the only tests widely carried out beyond the assessment of traffic assignment outcomes.
|
From page 68... ...
69 complex choice models. The urgency of addressing this issue was cited by several of the modelers encountered during the research for this report.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.