There are several recent efforts by cities to address the lack of information about the multimodal transportation impacts of new development. This is necessary to: assess development fees (or system development charges), maintain appropriate levels of service, provide supports for active transportation modes, estimate pollution emissions (including greenhouse gasses), site affordable housing projects, evaluate the health impacts, and manage parking demand. The data and methods currently available primarily rely on the Institute of Transportation Engineers (ITE) Trip Generation Handbook or models developed for regional demand forecasting. Both have well documented limitations when applied to urban sites, particularly given the multimodal focus of these new policies (Clifton, et al. 2015; Clifton, et al. 2012; Currans & Clifton, 2015; Shafizadeh et al. 2012; Millard-Ball, 2015; Weinberger et al. 2014). In addition, many urban land uses have features that do not fit within the traditional categories of uses for which data are available, including new multifamily housing developments that have recently entered the market. These include “micro” apartments, bicycle-oriented housing, apartments with vehicle (car and bicycle) sharing arrangements, and while not new, transit-oriented development.
To help address these issues, this research aims to: a) develop, test and implement a methodology to collect information about multimodal trip generation and the vehicle ownership and use of residents and visitors at multifamily sites, and b) develop an approach to assess the transportation impacts of these multifamily housing land uses. To do this, we propose a national study of affordable and market-rate multifamily housing sites that makes use of transportation counts and intercept surveys collected on site and a (mail out or online) modified household travel survey of residents and on-site property managers/employees. The study will leverage several concurrent or recent trip generation studies in various locations across the United States. These will permit standardization in data collection, pooling of data for analysis, comparison across locations, and control for more attributes of residents and the site. The data from these sites will be analyzed using multivariate statistical techniques and new tools for assessing travel impacts for multifamily housing projects will be developed.
The products of this research include: advances in data collection methodology, a means to estimate transportation impacts of new multifamily development, and a substantial database of multimodal multifamily trip generation information. The benefits of this project contribute to better coordination of land use and transportation, the advancement of multimodal transportation data and methods, and development of network of professionals and academics motivated to change practice.