Skip to main content

Currently Skimming:


Pages 25-34

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 25...
... 25   Step-by-Step Notes on Running the R Codes with Data A P P E N D I X This appendix provides a step-by-step tutorial on executing the codes developed in the Apollo Choice Modeling framework with R The R notebooks were prepared for all models included in the guide.
From page 26...
... 26 New Mobility Options in Travel Demand Forecasting and Modeling: A Guide Step 2 Second, initialize the Apollo Choice Modeling framework by specifying the model name and description and setting the output directory. Each individual record in the dataset has been assigned to a unique identifier, which is represented by the variable "id" in the dataset and provided here in the box marked red.
From page 27...
... Step-by-Step Notes on Running the R Codes with Data 27   Here, Choice = Vehicle ownership level veh0 = zero-vehicle HHs veh1 = HHs with one vehicle veh2= HHs with two vehicles veh3 = HHs with three or more vehicles wrktodrv = Ratio of workers to drivers age615todrv = Ratio of people aged 6–15 to drivers age1824todrv = Ratio of people aged 18–24 to drivers age80todrv = Ratio of people aged 80 or older to drivers inc_10 = HH income <= $10,000 inc_1030 = $10,000 < HH income <= $30,000 inc_60100 = $60,000 < HH income <= $100,000 Here, 1 = HHs with zero vehicles 2 = HHs with one vehicle 3 = HHs with two vehicles 4 = HHs with three or more vehicles
From page 28...
... 28 New Mobility Options in Travel Demand Forecasting and Modeling: A Guide Step 4 Fourth, set the initial values for the vector of parameters that will be estimated during the model estimation process. Each element in this vector corresponds to a specific parameter in the choice model framework.
From page 29...
... Step-by-Step Notes on Running the R Codes with Data 29   b_80todrv_veh1 = Coefficient for ratio of people aged 80 or older to drivers to drivers (HHs with one vehicle) b_inc10_veh2 = Coefficient for household income <=$10,000 (HHs with two vehicles)
From page 30...
... 30 New Mobility Options in Travel Demand Forecasting and Modeling: A Guide Step 6 Sixth, execute the model estimation procedure.
From page 31...
... Step-by-Step Notes on Running the R Codes with Data 31   Step 7 Finally, model outputs are generated by the following command. The outputs will match the estimates shown in Table 3.4 of the guide.
From page 32...
... 32 New Mobility Options in Travel Demand Forecasting and Modeling: A Guide
From page 33...
... Abbreviations and acronyms used without denitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America's Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration GHSA Governors Highway Safety Association HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012)
From page 34...
... Transportation Research Board 500 Fifth Street, NW Washington, DC 20001 ADDRESS SERVICE REQUESTED ISBN 978-0-309-70982-8 9 7 8 0 3 0 9 7 0 9 8 2 8 9 0 0 0 0

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.