Comment from Jacob Wasserman

Comment submitted on my own behalf, not representing my employer or any other affiliation: Adapted from: Wasserman, J., and Taylor, B. (2021, January 20). Sources of and Gaps in Data for Understanding Public Transit Ridership (UC-ITS-2020-33). UCLA Institute of Transportation Studies. https://doi.org/10.17610/t66893. Recommendation: Linked trips (transfers within or between operators) Explore the feasibility of including linked trip counts or estimates in the NTD (potentially drawing on regional transit smartcard data); provide operators methodology and resources from FTA to do so Across time periods, NTD datasets measure ridership as unlinked passenger trips (UPT), often called "boardings." The way ridership is defined is of critical importance, as consumption of transit is quite often—perhaps most often—the dependent variable of analyses that draw from these datasets. For operators that neither track nor discount transfers—instead charging the full fare for every boarding—collecting UPT data most closely matches their operations. However, many operators do offer transfer discounts or free transfers. Indeed, many subway systems—whose stations are split by fare gates into fully delineated paid and free areas—do not count boardings separately at all, since passengers transfer between trains without passing through fare gates. For example, while one such system, Bay Area Rapid Transit (BART), collects and disseminates among the most comprehensive datasets of any American transit agency (including origin-destination matrices between every pair of stations every month)—their staff nevertheless must submit UPT estimates to the NTD instead of counts, for this reason. Not only do unlinked trips fail to capture the way many transit systems operate, their use in datasets could potentially cause misleading trends. For instance, a number of bus operators like Houston Metro have restructured their entire networks into grid-like systems, wherein service along trunk routes is now more frequent and a greater share of journeys require a transfer. A resulting increase in UPTs could represent evidence of a successful redesign that has attracted more riders—but could also indicate that the same number of travelers, taking the same number of journeys, simply had to make more transfers, which research shows that riders generally dislike and seek to minimize. For this reason, the NTD should also explore with its reporting operators ways to manageably and reliably include measurements of linked trips as well, which, for most analyses, better reflect trends in the consumption of transit. Of course, this will require many operators to estimate linked trip counts, but, as many other operators already estimate unlinked trip counts (not to mention passenger miles traveled and other metrics), this should not significantly change the overall reliability of the data. Even if added to the NTD, these linked trip counts by individual operators may nonetheless exclude transfers between different agencies. In areas with fragmented transit operators, these transfers may make up a substantial share of transit use. Some operators do track inter-agency transfers, though, as a part of offering smart card discounts for transfers. These numbers too should be reported to the NTD where available, to give a fuller picture of transit use across regions.