While some activities have not produced tools or applications that are publicly available, several studies are mentioned in this section to illustrate existing examples of agencies leveraging GTFS data as part of their own research or planning studies. The Delaware Valley Regional Planning Commission has used GTFS data as the main source of data when developing its regional forecasting model <ref>Christopher M. Puchalsky, Drashti Joshi, and Wolfgang Scherr (2012), "Development of a Regional Forecasting Model Based on Google Transit Feed," in Transportation Research Board 91st Annual Meeting, Washington, DC, USA, p. 17, January 22, 2012. </ref>. The Brookings Study of Transit and Jobs in America <ref>Adie Tomer, Elizabeth Kneebone, Robert Puentes, and Alan Berube (2011). "Missed Opportunity: Transit and Jobs in Metropolitan America." Available at http://www.brookings.edu/~/media/Files/Programs/Metro/jobs_transit/0512_jobs_transit.pdf</ref> used GTFS data to determine how well transit connects people with their jobs. A research project by the National Center for Transit Research identified opportunities to use GTFS data to support service planning and operational activity and developed a prototype application that integrated GTFS data with an automatic passenger counter (APC) for analysis and visualization <ref>Martin Catala, Samuel Downing, and Donald Hayward (2011). "Expanding the Google Transit Feed Specification to Support Operations and Planning," National Center for Transit Research, November 15, 2011. Available at http://www.nctr.usf.edu/2011/11/expanding-the-google-transit-feed-specification-to-support-operations-and-planning-2/</ref>.