This thorough study of a 111-mile regional trail network around Columbus, Ohio found that trail users travelled roughly 11.9 million miles in 2014, mostly by bicycle. Higher population density, easy access from neighborhoods, connection to other trails, and longer trails are associated with greater use.
Lindsey, G., T. Nordstrom, X. Wu, C. Wu, J. Ciabotti, B. B. Woods, R. J. Eldridge, et al. 2015. The Impacts of Central Ohio Trails. Prepared for the Mid-Ohio Regional Planning Commission and the Central Ohio Greenways and Trails Group. Minneapolis, MN: University of Minnesota Humphrey School of Public Affairs.