Applying Census Data for Transportation

Mario Scott and Megan Brock of Steer Davies Gleave’s New York office attended Transportation Research Board’s conference in November on Applying Census Data for Transportation: 50 Years of Transportation Planning Data Progress.

Mario presented his poster, ‘A Case Study Measuring the Effect of the Margin of Error in CTPP (Census Transportation Planning Product) Data on Transit Business Planning’. His work revisited a project Steer Davies Gleave completed in 2013 for Kitsap Transit, which involved ferry ridership modeling as part of a business plan for their ferry system. Census data was an essential input, but in Steer Davies Gleave’s experience, margins of error on Census data are generally ignored in travel demand forecasting. Mario performed a case study testing the effects of the margin of error on the business plan outcomes of the work completed for Kitsap Transit. Mario found that the business plan was largely unaffected by the CTPP’s margins of error. Target revenues could have been met with as much as a 19% reduction in the base journey to work data, confirming the robustness of the study and providing confidence in the use of the dataset.

Megan presented in a breakout session on ‘Using Census Data to Understand Alternative Modes’. As Census data is central to demand forecasting for ferry services, she outlined how Steer Davies Gleave breaks down the CTPP data, the challenges when applying CTPP data, and decisions between using CTPP data based on the decennial Census versus continuous American Community Survey (ACS). Megan used the Citywide Ferry Study and the Kitsap Transit Passenger-Only Ferry Long-Range Strategy to highlight both the essential nature of the CTPP data and the differences in decision-making regarding the data based on the project context.

Overall, Mario and Megan found the conference presentations fascinating, particularly with respect to how different agencies and companies use Census data for such a wide array of transportation planning practices. The coordination between Census data and big data sources was a very interesting topic to many attendees. There are many ways the datasets can complement each other, including developing safety assessments or forecasting bike share use based a combination of Census and big data. The conference participants expressed excitement for the advancement of transportation planning practices and the upcoming 2020 Census.