pith. sign in

arxiv: 2605.23333 · v1 · pith:OM4KYKU5new · submitted 2026-05-22 · 📡 eess.SY · cs.SY

Safety-Assured Arrival Scheduling in Sequential UAM Corridor Sections under Speed and Separation Constraints

Sasinee Pruekprasert , Shinji Nakadai , Katsuhiro Nishinari This is my paper

Pith reviewed 2026-05-25 04:00 UTC · model grok-4.3

classification 📡 eess.SY cs.SY
keywords urban air mobilityarrival schedulingETA gapcorridor sectionsseparation constraintsspeed limitssafety assurancescheduling framework
0
0 comments X

The pith

Computing a sufficient ETA gap at constrained waypoints guarantees longitudinal separation in sequential UAM corridor sections with heterogeneous speed limits.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper proposes an analytical method for computing the minimum ETA gap needed at waypoints to ensure safe longitudinal separation in UAM corridors divided into sections with different speed limits. The gap is calculated using the section travel times, speed bounds, and the required separation distance, making it quick to check for scheduling. If the claim holds, schedulers can assign arrival times at waypoints that automatically prevent collisions throughout the entire corridor. Numerical tests in a corridor with decreasing speeds confirm that vehicles using this gap maintain spacing and improve flow over random arrivals.

Core claim

The authors present a safety-assured arrival-scheduling framework for Urban Air Mobility corridor operations. They introduce an analytical method to compute a sufficient ETA gap at Constrained Waypoints that guarantees longitudinal separation along sequential corridor sections with heterogeneous speed limits. This ETA-gap condition depends on section-specific speed bounds and the required separation distance. The computed ETA gap ensures safe separation across all corridor sections under prescribed section travel times and speed limits, as confirmed by numerical simulations in a decreasing-speed corridor.

What carries the argument

The ETA-gap condition at Constrained Waypoints, an analytical expression depending on speed bounds and separation distance that guarantees separation in sequential sections.

Load-bearing premise

Section travel times and speed limits are prescribed and known in advance.

What would settle it

A case where two vehicles meet the computed ETA gap at the waypoint yet violate the required separation distance inside one corridor section would disprove the guarantee.

Figures

Figures reproduced from arXiv: 2605.23333 by Katsuhiro Nishinari, Sasinee Pruekprasert, Shinji Nakadai.

Figure 1
Figure 1. Figure 1: A UAM corridor network with ETAs at CWPs. [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Conservative spatiotemporal bounds of vehicles [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Relationship between safeD and ti,i`1 [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Number of vehicles that safely arrived at CWP [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
read the original abstract

This paper presents a safety-assured arrival-scheduling framework for Urban Air Mobility (UAM) corridor operations. We propose an analytical method to compute a sufficient ETA gap at Constrained Waypoints (CWPs) that guarantees longitudinal separation along sequential corridor sections with heterogeneous speed limits. The resulting ETA-gap condition depends on section-specific speed bounds and the required separation distance, providing an efficiently computable rule suitable for integration into future digital ETA-scheduling and air traffic management systems. We show that the computed ETA gap ensures safe separation across all corridor sections under prescribed section travel times and speed limits. Numerical simulations for a decreasing-speed corridor confirm that vehicles coordinated with the proposed mechanism adjust their speeds to maintain the required spacing, avoid potential collisions, and support improved traffic flow compared with unscheduled operations.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 2 minor

Summary. The paper presents an analytical method to compute a sufficient ETA gap at Constrained Waypoints (CWPs) that guarantees longitudinal separation along sequential UAM corridor sections with heterogeneous speed limits. The ETA-gap rule is derived from section-specific speed bounds and the required separation distance; it is shown to ensure safe separation under prescribed section travel times and speed limits, with numerical simulations in a decreasing-speed corridor confirming that coordinated vehicles maintain spacing and improve flow relative to unscheduled operations.

Significance. If the derivation is correct, the work supplies an efficiently computable, input-driven safety rule suitable for digital ETA scheduling in UAM corridors. Credit is due for the explicit scoping to prescribed travel times and speed limits, the parameter-free character of the resulting gap condition, and the provision of simulation confirmation that the rule maintains separation.

minor comments (2)
  1. The abstract states that the ETA gap 'ensures safe separation across all corridor sections,' but the manuscript should explicitly state the theorem or proposition number that contains the formal guarantee and the precise assumptions under which it holds.
  2. Simulation results are described only qualitatively ('adjust their speeds to maintain the required spacing'); the manuscript should report quantitative metrics such as minimum observed separation distance, number of vehicles, and corridor parameters so that the confirmation can be assessed.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive summary, significance assessment, and recommendation of minor revision. The report lists no specific major comments to address.

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper derives an analytical ETA-gap rule directly from prescribed inputs (section travel times, speed bounds, and separation distance) to enforce longitudinal separation. The guarantee holds by construction within the declared regime of known parameters; simulations serve only as confirmation. No self-definitional reductions, fitted inputs renamed as predictions, or load-bearing self-citation chains appear in the provided claims or abstract. The derivation is therefore self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the domain assumption that section travel times and speed limits are prescribed; no free parameters or invented entities are mentioned in the abstract.

axioms (1)
  • domain assumption Section travel times and speed limits are prescribed and known in advance.
    The ETA gap computation depends directly on these quantities as stated in the abstract.

pith-pipeline@v0.9.0 · 5672 in / 1102 out tokens · 28558 ms · 2026-05-25T04:00:33.642832+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

12 extracted references · 12 canonical work pages

  1. [1]

    Ambrosio-L´ azaro, R.C., Quezada-T´ ellez, L.A., and Rosas- Jaimes, O.A. (2018). Parameter identification on Helly’s car-following model. InProc. of 5th International Conference of Control, Dynamic Systems, and Robotics (CDSR’18),

    work page 2018

  2. [2]

    Asslouj, A.E., Uppaluru, H., Ramezani, M., Atkins, E., and Rastgoftar, H. (2024). A fixed air corridor model for UAS traffic management in urban areas.IEEE Transac- tions on Aerospace and Electronic Systems, 60(5), 5651–

    work page 2024

  3. [3]

    and Rakas, J

    Bauranov, A. and Rakas, J. (2021). Designing airspace for urban air mobility: A review of concepts and ap- proaches.Progress in Aerospace Sciences, 125, 100726. Fontaine, P. (2023). Urban air mobility concept of operations v2.0. Federal Aviation Administration, Office of NextGen. URLhttps://www.faa.gov/sites/ faa.gov/files/Urban%20Air%20Mobility%20%28UAM%...

    work page 2021

  4. [4]

    Lee, U.J., Ahn, S.J., Choi, D.Y., Chin, S.M., and Jang, D.S. (2023). Airspace designs and operations for UAS traffic management at low altitude.Aerospace, 10(9),

    work page 2023

  5. [5]

    Li, H., Roncoli, C., and Ju, Y. (2024). A Helly model- based MPC control system for jam-absorption driving strategy against traffic waves in mixed traffic.Applied Sciences, 14(4),

    work page 2024

  6. [6]

    Muna, S.I., Mukherjee, S., Namuduri, K., Compere, M., Akbas, M.I., Moln´ ar, P., and Subramanian, R. (2021). Air corridors: Concept, design, simulation, and rules of engagement.Sensors, 21(22),

    work page 2021

  7. [7]

    and Nakadai, S

    Pruekprasert, S. and Nakadai, S. (2025). Safe arrival scheduling at constraint waypoints in UAM corridors. InProc. of AIAA SciTech 2025 Forum,

    work page 2025

  8. [8]

    Smith, N.M., Brasil, C., Lee, P.U., Buckley, N., Gabriel, C., Mohlenbrink, C.P., Omar, F., Parke, B., Speridakos, C., and Yoo, H.S. (2016). Integrated demand manage- ment: Coordinating strategic and tactical flow schedul- ing operations. InProc. of 16th AIAA Aviation Tech- nology, Integration, and Operations Conference,

    work page 2016

  9. [9]

    Thipphavong, D.P., Apaza, R., Barmore, B., Battiste, V., Burian, B., Dao, Q., Feary, M., Go, S., Goodrich, K.H., Homola, J., et al. (2018). Urban air mobility airspace integration concepts and considerations. InProc. of 2018 Aviation Technology, Integration, and Operations Conference,

    work page 2018

  10. [10]

    and Hansman, R.J

    Vascik, P.D. and Hansman, R.J. (2018). Scaling con- straints for urban air mobility operations: Air traffic control, ground infrastructure, and noise. InProc. of 2018 Aviation technology, Integration, and Operations conference,

    work page 2018

  11. [11]

    Wang, Z., Delahaye, D., Farges, J.L., and Alam, S. (2021). Air traffic assignment for intensive urban air mobility operations.Journal of Aerospace Information Systems, 18(11), 860–875. Wing, D., Lacher, A., Ryan, W., Cotton, W., Stilwell, R., Maris, J., and Vajda, P. (2022). Digital flight: A new cooperative operating mode to complement VFR and IFR. URLht...

    work page 2021

  12. [12]

    Yokoyama, N., Shindo, M., Matayoshi, N., and Yoshida, H. (2025). Performance evaluation of UATM services accounting for airspace and vertiport capacities. InProc. of AIAA SciTech 2025 Forum, 2696

    work page 2025