Another Look at the Question of Density and Rail Transit

Long community discussions about rail often include whether a city's spatial distribution of housing, employment and other trip generators is conducive to supporting rail transit. A city's decision to construct rail transit is based on an array of variables, some of which may indirectly relate to density. Other variables considered important are number of new riders, operating costs and construction costs. Although density is not a direct variable in the list of criteria, numerous studies show a positive correlation with ridership, confirming density as an explanation for the number of riders a system will attract. For that reason, opponents of new rail systems often raise lack of density as reason not to pursue rail. This research compares density in a few select cities with the accepted transit efficiency performance measure of operating cost per passenger mile to determine whether this statistic is better in more dense cities.