Takara Sakai - Personal Home Page

Profile

Name and affiliation

• Takara Sakai
• Specially Appointed Assistant Professor, School of Environment and Society, Institute of Science Tokyo (Takayama Lab)
• Curriculum vitae: cv

Appointment

• 2024.10-　Specially Appointed Assistant Professor, School of Environment and Society, Institute of Science Tokyo
• 2023.10-2024.09　Specially Appointed Assistant Professor, School of Environment and Society, Tokyo Institute of Technology
• 2020.04-2023.09　Research Fellow of the Japan Society for the Promotion of Science (DC1)

Education

• Ph.D. Information Science, Tohoku University, 2023 (Supervisor: Prof. Akamatsu)
• M.S. Information Science, Tohoku University, 2020
• B.S. Civil Engineering, Tohoku University, 2018
• Tokyo Metropolitan Toyama High School, 2014

Contact address

• Email: sakai.t.dcad@m.isct.ac.jp
• Mailing address: W6-9, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
• Building and office: Room 410, West Bldg. 6, Ookayama Campus, Institute of Science Tokyo
• researchmap
• Google scholar
• GitHub
• Blog
• Kurumido LLC

Research interests

• Transportation and Traffic Theory
• Regional Science and Urban Economics
• Optimization, Control, Algorithm, Game, Mechanism and Data

Collaboration

• I welcome collaboration and academic exchange at conferences and elsewhere. Please feel free to contact me.

Support my research

• I am always seeking financial support for my research. Both individuals and corporations may be eligible for tax benefits (donation deduction). I would be grateful if you could consult me in advance.
• For details of the scheme, please see Donation methods | Science Tokyo.

Preprints / Working papers / MISC

1. Takara Sakai and Riki Kawase, 2026.
   Coarse Preference Reporting in the Bottleneck Model: Approximate Strategyproofness and Efficiency
   https://arxiv.org/abs/2606.17400
2. Mingzhi Xiao, Takara Sakai, Daisuke Murakami and Yuki Takayama, 2025.
   When Does Tourism Raise Land Prices? Threshold Effects, Superstar Cities, and Policy Lessons from Japan
   https://arxiv.org/abs/2509.04307
3. Shota Fujishima, Takara Sakai and Yuki Takayama, 2025.
   Quantifying Congestion Externalities in Road Networks: A structural estimation approach using stochastic evolutionary model
   RIETI Discussion Paper Series 25-E-055
4. Takara Sakai, Koki Satsukawa and Takashi Akamatsu, 2022.
   Non-existence of queues for system optimal departure patterns in tree networks
   https://arxiv.org/abs/2205.06015

Publications

1. Takara Sakai, Takashi Akamatsu and Koki Satsukawa, 2026.
   Queue Replacement Approach to Dynamic User Equilibrium Assignment with Route and Departure Time Choice
   Transportation Research Part B: Methodological, 211, 103523.
   (preprint version arXiv)
2. 酒井 高良, 高山 雄貴，2025.
   需要主導型の輸送ネットワーク形成：Hub and Spoke構造の創発
   土木学会論文集, Vol.81, No.6, ID:24-00167.
   (preprint version Jxiv)
3. Takara Sakai, Takashi Akamatsu and Koki Satsukawa, 2024.
   Queue replacement principle for corridor problems with heterogeneous commuters
   Transportation Research Part B: Methodological, 187, 103024.
   (preprint version arXiv)
4. Takara Sakai, Takashi Akamatsu and Koki Satsukawa, 2024.
   A Paradox of Telecommuting and Staggered Work Hours in the Bottleneck Model
   Transportation Science, 58(6), pp.1335-1351.
   (preprint version arXiv)
5. 酒井 高良, 涌井 優尚, 赤松 隆, 2023.
   超大規模離散空間におけるFujita-Ogawaモデルの効率的解法
   土木学会論文集, Vol.79, No.4.
   (preprint version Jxiv)
6. 涌井 優尚, 酒井 高良, 赤松 隆, 2023.
   大規模ネットワークにおける動的利用者均衡配分の効率的解法
   土木学会論文集, Vol.79, No.4.
   (preprint version Jxiv)
7. 酒井 高良, 赤松 隆, 佐津川 功季, 2021
   スケジュールコストの異質性を考慮したタンデムボトルネック出発時刻選択問題
   土木学会論文集D3(土木計画学), Vol.77, No.4, pp.330-345.
8. Takashi Akamatsu, Takeshi Nagae, Minoru Osawa, Koki Satsukawa, Takara Sakai and Daijiro Mizutani, 2021.
   Model-based analysis on social acceptability and feasibility of a focused protection strategy against the COVID-19 pandemic
   Scientific Reports 11, 2003.
   (preprint version MedRxiv )
9. 酒井 高良, 赤松 隆, 2019
   首都圏高速道路網における渋滞パターンとMacroscopic Fundamental Diagramの安定性
   土木学会論文集D3(土木計画学), Vol.75, No.2, pp.97-108.

Scheduled Presentations (International Conference)

1. Takara Sakai, Takashi Akamatsu and Koki Satsukawa.
   Queue Replacement Approach to Dynamic User Equilibrium Assignment with Route and Departure Time Choice
   The 26th International Symposium on Transportation and Traffic Theory, Munich, Germany, 2026.07
2. Takara Sakai and Yasunari Hikima.
   Inverse Optimal Transport for Bottleneck Models: Estimating Temporal Travel Demand Distributions
   INFORMS Transportation and Logistics Society Third Triennial Conference (TSL Conference), MIT, Massachusetts, USA, 2026.07

Presentations (International Conference)

1. Mingzhi Xiao, Takara Sakai and Yuki Takayama.
   High-Speed Rail and Population Agglomeration in China: Implications for Urban Planning and Regional Development
   World Conference on Transport Research (WCTR) 2026, Toulouse, France, 2026.07.06-10
2. Mingzhi Xiao, Yuki Takayama and Takara Sakai:
   The Role of High-Speed Rail in Shaping Chinese County-Level Economic Structures
   HKSTS @Hong Kong 2025.12
3. Takara Sakai, Takashi Akamatsu and Koki Satsukawa.
   A Paradox of Telecommuting and Staggered Work Hours in the Bottleneck Model
   The 25th International Symposium on Transportation and Traffic Theory, Ann Arbor, Michigan, United States, 2024.07.15-17.
   Slide
4. Takara Sakai
   A Paradox of Telecommuting and Staggered Work Hours in the Bottleneck Model
   International seminar @Huazhong University of Science and Technology, Wuhan, China 2024.03.28
5. Takara Sakai, Takashi Akamatsu, Koki Satsukawa:
   Welfare impacts of remote and flexible working policies in the bottleneck model
   11th Symposium of the European Association for Research in Transportation @ETH Zurich 2023.09.08
6. Takara Sakai, Takashi Akamatsu, Koki Satsukawa:
   Queue replacement principle for corridor problems with heterogeneous commuters
   9th International Symposium on Dynamic Traffic Assignment @Northwestern University 2023.07.11
7. Takara Sakai, Takashi Akamatsu, Koki Satsukawa:
   Departure time choice problems in a corridor network with heterogeneous value of schedule delay
   The 25th HKSTS International Conference @online 2021.12.10
8. Takara Sakai, Takashi Akamatsu：
   Spatio-Temporal Regularities of Traffic Congestion Patterns in the Metropolitan Expressway Network
   The 5th CWRU-Tohoku Joint Workshop @Tohoku University 2018.08.02

Grants

1. 待ち行列置き換え原理に基づく動的利用者均衡配分理論の再構築
   JSPS KAKENHI, Grant-in-Aid for Early-Career Scientists (No. 26K17486), 2026.04-2029.03
   Principal Investigator
2. 協調・非協調車両が混在する道路交通ネットワークシステムの数理解析
   Obayashi Foundation, Research Grant, 2026.04-2027.03
   Principal Investigator
3. 東京科学大学社会連携・DE&I本部DE&I部門 アシスタント配置プログラム
   Institute of Science Tokyo, DE&I Division, Assistant Placement Program, 2025.04-2026.09
   Principal Investigator
4. Max-Plus 代数を用いた輸送システムの安定性解析
   Tokyo Institute of Technology (Institute of Science Tokyo), Academy for Broad-based Basic Research, New Research Development Incentive Grant, 2024.09-2026.03
   Co-investigator (PI: Riki Kawase)
5. 車両間の情報共有と戦略共有を表現・操作可能な交通ネットワーク均衡モデルの開発
   JSPS KAKENHI, Grant-in-Aid for Research Activity Start-up (No. 24K22973), 2024.08-2027.03
   Principal Investigator
6. 時空間スケールの異なる通勤渋滞緩和施策の相補的・相反的効果
   Obayashi Foundation, Research Grant, 2024.04-2025.03
   Principal Investigator
7. 都市高速道路網における渋滞パターン情報を活用した交通制御：渋滞をもって渋滞を制す
   JSPS KAKENHI, Grant-in-Aid for JSPS Fellows (No. 20J21744), 2020.04-2023.03
   Principal Investigator