Suggested Citation:
Handy, Susan L., Kevan R. Shafizadeh, Robert Schneider (2013) Final Report: California Smart-Growth Trip Generation Rates Study. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-13-58

The Institute of Transportation Engineers’(ITE), Trip Generation Manual provides estimates of the number of trips per unit size that a new development is likely to generate. Most of the data on which ITE bases its trip-generation rates is obtained at suburban locations. As a result, these rates may not accurately reflect the trip generation patterns at smart growth sites where close proximity to other destinations as well as transit and bike facilities make non-vehicular forms of travel more prevalent.

To address this bias, Schneider et al. (2013a) developed a methodology for producing more accurate trip-generation rates for smart growth sites across California. The original study produced a data collection methodology, a smart growth factor incorporating 8 variables representing the degree to which a site reflects smart growth characteristics, trip generation adjustment models for both AM and PM peak hours, and a spreadsheet tool for use by practitioners. The trip-generation models were based on data from more than 50 sites in California. Validation of these models was conducted using data from several sites left out of the estimation process.

Follow-up work was done to test and improve the PM model developed in the original study. The follow-up work supplements the original trip generation data collected in California with data collected at 78 sites in the Portland region by Kelly Clifton and others (2012) at Portland State University. These new sites were located across the Portland area in both smart growth and non-smart growth developments. The following sections describe the work done to verify the original model, re-estimate a new PM model based on the combined dataset, and conduct validation.

Keywords: Transportation Modeling, Smart Growth, Urban In-fill, Land Use, Methodology, Vehicle Trips, Mitigation, Institute of Transportation Engineers, ITE, Trip Generation Manual, Trip-Generation Rates, California Study, Portland Oregon Study, pedestrian, bicycle, transit, automobile