To understand the travel impacts of new development, cities often rely on the Institute of Transportation Engineer’s Trip Generation Report, which is designed to represent trip rates in areas with single-use, low-density zoning and land uses. Washington, D.C., in contrast, is primarily dense and mixed-use with many options to walk, bike, and take transit. The District Department of Transportation (DDOT) needed a better way to estimate trips and travel impacts.
Nelson\Nygaard worked with DDOT to create a data collection protocol in advance of developing a multimodal trip generation model suited to urban contexts. A pilot survey effort ground proofed the method. The data were tested against available modeling tools, including ITE’s trip generation; none of the available tools proved to be a good predictor, validating the need for new models.
In collaboration with DDOT, Nelson\Nygaard created a database and model that can be used nationally to predict urban trip generation. The team formalized a peer-reviewed standard methodology for data collection with the ultimate goal of creating a nationwide open-source database of trip generation for various land uses in urban contexts.