MTC Appendix 1e GTFS feedback

[edasmalchi]

MTC has some questions about the GTFS-derived figures we provided for TTTF appendix 1e.

• Research Required:

Explain discrepancies between MTC model and our figures, correct as necessary.

Route-miles and (to a lesser extent) routes are significantly different than what is reflected in the MTC travel model, which is a fairly comprehensive/non-duplicative inventory including all of the region’s operators. Our estimated route-mileage is ~13K, whereas Appendix A estimates 22K; our estimated route total is 1,060, whereas Appendix A estimates 769.

No obvious error, we should check in with MTC about their definition of route-miles. I've counted each direction separately (use two longest GTFS shapes), could they count a single line for both directions? Also, which agencies does their model include?

Santa Barbara’s primary bus operator (MTD) only has about 20 routes; while there are likely a handful of other small operators with routes in Santa Barbara County, it’s unlikely they have 156 routes in that one county per the findings in Appendix A. Same with San Diego – primary bus operator MTS has about 100 bus routes; even with the trolley lines & NCTD, it’s unlikely that there are 357 bus lines in that county.

Both of these regions have m:1 agency to feed relationships, we should correct our analysis.

Conversely, square mileage of high-quality transit coverage seems to be somewhat in the right ballpark. While MTC’s data analysis doesn’t exactly match what is included in Appendix A, this may be due to different data vintages or usage of different “high quality transit” definitions (e.g., 15 vs 20 min headways).

Glad this largely matches, our data reflects May 2025 which I believe is a few years more recent than MTC's.

• Expected Outputs / Findings: what do you hope to have created when this is complete?

TTTF 11 Report Feedback Form_MTC_comments.pdf

Updated figures, documented methodology for TTTF appendix.

[edasmalchi]

Methodology

Route Mileage and Number of Routes

First, we spatially overlay GTFS-derived routes with Metropolitan Planning Organization boundaries. If a route crosses an MPO boundary, it will be counted in both regions. However, mileage counts will include only the portion of the route's mileage within that MPO region to avoid double counting.

For this analysis, we've added a deduplication step to only keep unique route_id and shape_id for each GTFS feed. In some cases, multiple agencies share a GTFS feed. This avoids double counting routes, but in those cases agency metadata from this analysis may not be accurate.

Our methodology aims to count mileage in each direction of a route. This is implemented by keeping the two longest GTFS shapes for each route, which generally correspond to the longest service pattern in each direction. Where multiple routes interline, we count mileage of each route separately.

To count the number of routes, we count the number of unique GTFS route_id.

Questions for MTC:

• How does MTC define route-miles? Are you able to share GIS data of routes from the MTC travel model as well as a list of unique routes with operator information? These will help us refine our analysis.

[edasmalchi]

waiting on Hunter to schedule a meeting

[edasmalchi]

sent our data and methods to MTC before vacation, will follow up soon

[edasmalchi]

followed up Aug 7