This page is intended to serve as a resource for users of trip generation tools and research. It should be noted the resources posted here have not been reviewed or approved by ITE. They are presented here to increase user's awareness of related research and tools that are currently available. If you have ideas or thoughts for additional content on this page, please forward this information to Dan Hardy for consideration.
This spreadsheet is referenced in the Trip Generation Handbook, 3rd Edition, page 46. The section of the handbook is shown below that explains the usage of the spreadsheet. NCHRP Report 684 can be referenced for more details as well.
6.5 Process for Estimating Mixed-Use Trip Generation
The recommended procedure for estimating internal trip capture and trip generation for a mixed-use development is a series of nine steps:
Step 1: Determine whether methodology is appropriate for study site.
Step 2: Estimate person trip generation for individual on-site land uses.
Step 3: Estimate proximity between on-site land use pairs.
Step 4: Estimate unconstrained internal person trip capture rates with proximity adjustment.
Step 5: Estimate unconstrained demand between on-site land use pairs.
Step 6: Estimate balanced demand between on-site land use pairs.
Step 7: Estimate total internal person trips between on-site land use pairs.
Step 8: Estimate total external person trips for each land use.
Step 9: Calculate overall internal capture and total external vehicle trip generation.
The spreadsheet tool automatically performs many of the required calculations based on input data.
If using the spreadsheet tool, the analyst needs to complete Steps 1 through 3. The estimation tool automatically calculates overall internal capture and total external vehicle trips in Steps 4 through 8 and summarizes the results. The complete step-by-step procedure is provided in Chapter 6 of the Handbook if the analyst chooses to do the calculations manually (if the analyst, for example, is using local data to supplement the national database). Appendix G contains an example application of the recommended process.
Source: An adaptation of a figure in NCHRP 684 (called Tables 103 and 104). Bochner, B., K. Hooper, B. Sperry, and R. Dunphy. NCHRP Report 684: Enhancing Internal Trip Capture Estimation for Mixed-Use Developments. Washington, DC: Transportation Research Board, 2011.
- NCHRP Project 08-51 (Active) Enhancing Internal Trip Capture Estimation for Mixed-Use Developments
The objective of this two-phase research project is to produce a methodology for enhancing internal trip capture estimates including (1) a classification system of mixed-use developments that identifies the site characteristics, features, and context that are likely to influence internally captured trips and (2) a data-collection framework for quantifying the magnitude of internal travel to and around mixed-use developments to determine the appropriate reduction rates.
Trip Generation Rates for Infill Developments
Trip Generation Rates at Transit-Oriented Developments
- TCRP H-27A (Completed) Ensuring Full Potential Ridership from Transit-Oriented Development
This study of transit-oriented development (TOD) is a national assessment of TOD issues, barriers, and successes. This project included evaluation of 10 case studies from a variety of geographic and development settings. This study indicates that increased ridership is the principal goal of transit agencies in supporting TODs. However, increased ridership as a result of TOD is a complex outcome involving behavioral, locational, and situational factors.
Freight Trip Generation
- NCFRP 25 (Active) Freight Trip Generation and Land Use (Jointly Funded as NCHRP 08-80) - Published as NCHRP Report 739 and NCFRP Report 19 (Joint Report)
NCHRP Report 739/NCFRP Report 19: Freight Trip Generation and Land Use provides a comprehensive discussion of how the freight system, and specifically freight trip generation and land use, relate. The report consolidates available freight trip generation models in an electronic database to assist practitioners interested in using these models; identifies the most appropriate approaches to develop and apply freight trip generation models; and estimates establishment-level freight trip generation models in a number of case studies. The case studies confirm the superiority of economic classification systems over standard land use classification systems as the foundation for estimating freight trip generation.
Traditional Neighborhood Developments
Multivariate Site Trip Generation
Investigations of the components of vehicle trip generation using tool such as multiple regression analysis have resulted in proposed relationships among independent variables and vehicle trips. Two existing models include:
- Index Planning Support Software which contains suggested elasticity equations relating trip generation rates to density, diversity, design, destinations, and distance to heavy rail (labeled "Index 5D"). The Index Plan Builder User Guide was prepared by Criterion Planners in 2007 and the relationships and source bibliography are contained in Appendix A to the guide.
- The Urbemis urban emissions model includes a module containing suggested trip reduction equations associated with site-level and areawide-level mitigation strategies. The users guide "Adjusting Site Level Trip Generation Using Urbemis" was prepared by Nelson/Nygaard Consulting Associates in 2005 and contains study references in its appendix.
Pedestrian and Bicycle Trip Generation
One of the greatest challenges facing the bicycle and pedestrian field is the lack of documentation on usage and demand. Without accurate and consistent demand and usage figures, it is difficult to measure the positive benefits of investments in these modes, especially when compared to the other transportation modes such as the private automobile.
- The National Bicycle & Pedestrian Documentation Program, co-sponsored by and Alta Planning and Design and the Institute of Transportation Engineers (ITE) Pedestrian and Bicycle Council is a nationwide effort to provide a consistent model of data collection and ongoing data for use by planners, governments, and bicycle and pedestrian professionals. Instructions for data collection, project description and forms are included on the web site.
Local Trip Generation Rates
Some jurisdictions have established localized trip generation rates for development approval based on observed characteristics in their community.
- Montgomery County, Maryland has provided trip generation equations and rates are provided for nine general land uses: general office, retail, residential, fast food restaurants, child day-care centers, private schools/educational institutions, senior/elderly housing, mini-warehouse, and automobile filling stations with or without ancillary uses for car washes, convenience stores, and garages. Appendices A-C of Local Area Transportation Review Guidelines: Guidelines of the Montgomery County Planning Board for the Administration of the Adequate Public Facilities Ordinance contain local trip generation rates.
Regional Travel Demand Models
Travel demand models use roadway and transit networks, population and employment data to calculate the expected demand for transportation facilities.