Interborough Express Ridership Projections – Part 2
John Pegram[1]
A new, sophisticated study from the C2SMARTER Center of the NYU Tandon School of Engineering[2] predicts a much higher Interborough Express (IBX) ridership than any prior study, more than 254 thousand weekday trips. This study comes with a considerable degree of credibility, both because of its source and became the project was partially funded by the U.S. Department of Transportation.[3]
The ever-increasing ridership predictions are indicators that the MTA’s January 2023 selection of partially street-running Light Rail was a bad choice for the IBX line.
In this Part 2 of my IBX ridership projections article, we will look at how IBX ridership predictions have evolved. A future article will consider unaddressed factors & consequences of the ridership predictions.
IBX Feasibility Study – Interim Report – Jan. 2022
At the beginning of January 2022, Governor Hochul announced the IBX project and the MTA published its 28 page Interborough Express – Interim Report – Feasibility Study and Analysis.[4] It estimated a 2020 population of 900 K people living within a half mile of the IBX corridor and predicted a weekday ridership of 87.8 thousand riders for the Light rail alternative, apparently in the year 2040.[5] The report said, “If built, the IBX would see higher daily ridership than nearly any new transit line built in the U.S. over the last two decades.” The published Interim Report mentioned a peak frequency of every five minutes and pictures 2-car Light Rail vehicles,[6] but the text did not discuss the number of railcars or their capacity.
Because ridership is stated in terms of one-way trips, and riders typically make round trips, the Interim Report’s ridership prediction meant the MTA expected only 43.9 K (4.9%) of that 900K population would be regular, weekday users of the IBX line. That struck me as much too low, as discussed in Part 1 of this article.[7]
The Interim Report apparently was based on a relatively low-key studies made by the MTA’s consultants before Governor Hochul’s formal involvement, when the project was known as the Bay Ridge Connector (BRC) study. The consultants’ BRC study reports became the Appendices for the IBX Interim Report.[8] Appendix 1.5 is a fairly detailed discussion of “Development of Ridership Forecasting & Analysis Tools.” Appendix 1.16: is a “Technical Report on Operational Analysis” and Appendix 1.17 provides “Ridership Estimates.” Buried within the unpublished Appendix 1.16 is the admission, “Originally two-car LRVs were envisioned. However, due to strong ridership projections, this was increased to three-car LRVs trainsets.”[9]
Planning and Environmental Linkages Study (PEL Report) – Jan. 2023
In January 2023, the MTA published its Planning and Environmental Linkages Study (PEL Report).[10] It said the Light Rail alternative would carry approximately 115,000 passengers each weekday in 2045. The report did not explain why the IBX Light Rail ridership prediction had been increased by almost 31% over the prediction in the Interim Report. The change in the year of ridership prediction, from 2040 in the Interim Report to 2045 in the PEL Report does not explain the change in predicted ridership. It is not explained by population change. The estimated 900K population in the IBX corridor in Year 2020 was the same in both reports, and both reports predicted a corridor population of 941K in 2045, only a 4.6% total increase over that in 2020.
Like the Interim Report, the PEL Report referred to a peak frequency of 5 minutes in each direction, but did not discuss the number of railcars or their capacity. It did say that Light Rail trains could be lengthened to meet demand.
The PEL Report also had an Appendix of underlying reports by the MTA’s consultants.[11] That Appendix said very little about ridership and provided no explanation for its increased ridership prediction.
MTA 20-Year Needs Assessment
In October 2023, the MTA published its 20-Year Needs Assessment,[12] identifying possible projects for its 2025-2029 Capital Program, which is scheduled to be published in fall 2024.[13] The IBX proposal received a top score is all but one category, which was described as “System Crowding—Passenger Hours in Crowded Conditions.” (This appears to have been the first public admission by the MTA of a crowding problem with its IBX Light Rail proposal). Total daily riders in 2045 was predicted to be 118.5K.[14]
2024 Ridership Comments from the MTA
MTA Construction President, Jamie Torres-Springer, said that “upwards of 120 to 150 thousand riders” were projected for the Interborough Express during a virtual meeting on April 29, 2024.[15] Then, on Friday, June 21st, cable TV station New York 1 referred to an expectation of 150 thousand riders when reporting on the new federal funding for IBX planning. I asked the MTA media relations office about these numbers and was told “There is no new ridership number. We’re always refining the model….” The representative indicated that the mentions of 150K were “illustrative,” presumably of the project’s potential.
Note that a prediction of 150K weekday riders in 2045 would indicate that only 75K (8%) of the 941K predicted 2045 population of the corridor would be regular users of the IBX line.
NYU Tandon School of Engineering Paper
A new paper, predicting IBX ridership of more than 254 thousand people, has been written by a group guided by Prof. Joseph Chow at the C2SMARTER Center of the NYU Tandon School of Engineering.[16] The ridership predictions in this paper appear to be primarily based on calculations of projected time-savings. The paper considers both travel in Brooklyn and Queens (the apparent primary focus of MTA reports) and beyond.
Prof. Chow has explained to me that the paper’s methodology uses expected transit travel time improvements in relation to the existing transit network in NYC to identify the populations that would benefit from that improvement, including those that may use the line as part of a transfer to other lines. The demand is estimated using classic transportation modeling concepts for predicting ridership (discrete choice models), although the authors did make some enhancements by making use of publicly available synthetic data from Replica to produce demand models for all of NY State.
According to this paper, the IBX could save 28.1 minutes for potential riders across the city. For travelers either going to or departing from areas close to the IBX line, the average time saving is projected to be 29.7 minutes.[17] Like Elif Ensari’s report on the NYU Marron Institute’s Transit Costs website,[18] mentioned in Part 1 of this article, the NYU Tandon School of Engineering paper found that trips associated with areas relatively far away from the IBX corridor, such as the JFK airport and midtown Manhattan, would also use IBX heavily, indicating its value in providing better transfer services to other parts of the city.[19]
Among the projected 254K daily riders, more than 78K (30.8%) would come from low-income households. 165 thousand people (64.7%) would start or end trips along the IBX corridor. The addition of IBX would attract more than 50K additional daily trips to transit mode, among which more than 16K would be switched from using private vehicles, reducing potential greenhouse gas (GHG) emissions by 29.28 metric tons per day.
Conclusion
The ever-increasing ridership predictions are indicators that Light Rail and street-running are bad choices for the IBX line.
In a future article, I will consider unaddressed factors & consequences of the ridership predictions.
This article expresses the personal views of the author and does not express the views of his employer, or any client or organization. The author has degrees in law and physics, and has taken several engineering courses. After five years of work as an engineer, he has practiced law primarily in the field of patents for over 50 years, dealing with a wide variety of technologies. He is a life-long railfan and user of public transportation in the United States, Europe and Japan.
As usual a PDF copy of this article is attached.
[1] © John Pegram, 2024.
[2] C2SMARTER is a Tier 1 USDOT University Transportation Center, working on real-world urban mobility problems from an engineering perspective. See https://engineering.nyu.edu/research-innovation/centers/c2smarter.
[3] Yang et al, “Welfare, sustainability, and equity evaluation of the New York City
Interborough Express using spatially heterogeneous mode choice models” (2024), prepublication copy available at https://arxiv.org/abs/2408.01562.
[4] MTA, Interborough Express – Feasibility Study and Alternatives Analysis – Interim
Report (Jan. 2022) (Interim Report), p. 16. The report without appendices is available from the MTA at https://new.mta.info/document/72081. The most complete version with appendices, produced to me in response to my Freedom of Information Law (FOIL) request, is available for download here. Citations to pages of this version, as indicated by a PDF reader, are in the form [###/1041].
[5] Although the year of predicted weekday ridership is not stated in the Interim Report, the predicted annual ridership in that report is for 2040 (Interim Report p. ) and the Ridership Forecasts in Appendix 1.17 refers to Year 2040 having been selected as the “horizon analysis year.” [781/1041].
[6] Interim Report, p. 16.
[7] Available at https://bqrail.substack.com/p/interborough-express-ridership-projections.
[8] The Interim Report Appendix does not appear to have been published by the MTA. I obtained a copy by a Freedom of Information Law request and posted it here.
[9] Id., Appendix 1.16, p. 9 [754/1041].
[10] MTA, Interborough Express Planning & Environmental Linkages Study (Jan. 2023) (PEL Report), including most appendices, is available from the MTA here. Citations to pages of that version, as indicated by a PDF reader, are in the form [###/1150].
[11] Id.
[12] MTA Press Release, “MTA Releases Assessment Outlining Needs to Continue Investing in $1.5 Trillion Regional Public Transportation System Over Next 20 Years,” available at https://new.mta.info/press-release/mta-releases-assessment-outlining-needs-continue-investing-15-trillion-regional. The Assessment is at
https://future.mta.info/
and the Detailed Appendix is at https://future.mta.info/documents/20-YearNeedsAssessment_FullAppendix.pdf. Assessment and Appendix pages referring to the IBX are attached.
[13] See MTA “20-Year Needs Assessment | Next Steps,” available at https://future.mta.info/next-steps/.
[14] 20-Year Needs Assessment Appendix pp. 209, 221 (attached)
[15] Regional Plan Association virtual assembly meeting, “The Age of Megaprojects,” video available at https://rpa.org/events/assembly/2024-assembly/assembly-2024-monday-megaprojects.
[16] Supra, note 3.
[17] Id., p. 1.
[18] Elif Ensari, NYU Marron Institute, Transit Costs Project, The Interborough Express Study, available at
https://ibx.transitcosts.com/
.
[19] Supra, note 3, p. 14.
Honestly, my familiarity with Tandon doesn't give any confidence in their prognostications.