Akihito Nagahama Lab.,
The University of Electro-Communications, Tokyo, Japan
Akihito Nagahama Lab.,
The University of Electro-Communications, Tokyo, Japan
October and November, 2025
Thank you to all the third-year students who joined the Lab. Introduction Session, social gathering, and subsequent lab visits!
We truly appreciate your active participation and interest!
October 23, 2025
Our paper, “Grouping mechanisms of vehicles in heterogeneous traffic with weak lane discipline: A single-site observational study focusing on leader–follower relations,” has been published in Physica A.
In this study, we automatically detected “vehicle groups (LF groups)”—clusters of vehicles moving in coordination—from road videos recorded in India and analyzed how these groups form and dissolve.
The findings suggest that the emergence and disappearance of such groups can be explained by a combination of the following three factors:
Similarity in driving behavior (speed and acceleration patterns)
Spacing and positioning relative to surrounding vehicles
Resistance to external intrusions (difficulty of being cut in by others)
In other words, even in the seemingly chaotic traffic of developing countries, there exists an underlying order shaped by human drivers through the formation and dissolution of groups.
Understanding this mechanism could eventually contribute to improving traffic systems in contexts where strict rules or lane discipline are not easily enforced.
You can read the paper here: Link to accepted ver. (License: CC BY-NC-ND)
September 27–28, 2025
Our lab went on a trip to Ito and Atami Onsen!
We had some great in-depth conversations and exchanges that we don’t usually get to have during our regular lab days. Let’s do it again sometime!
September 26, 2025
Our undergraduate students gave their midterm presentations for their graduation research.
They delivered clear and well-prepared presentations, which led to productive and insightful discussions!
August 7, 2025
Our master’s student scheduled to graduate this fall delivered their final thesis presentation.
Through dedicated practice and feedback sessions within the lab, they achieved an excellent and polished presentation!
June 30, 2025
We held a summer gathering to beat the heat!
It’s a busy time for everyone, but let’s stay focused and keep up the good work!
April 30, 2025
Our paper, “Effect of Response Time Distribution in Weak Lane Discipline on Linear Stability,” has been published in Collective Dynamics.
In this study, we investigated how variations in drivers’ reaction times affect the growth of deceleration waves in lane-less traffic, using both experimental data and theoretical analysis.
The results revealed that lane-less traffic is more prone to the growth of deceleration waves and to flow instability than previously predicted by conventional theoretical models.
You can read the paper here: Link to published ver.
April 24, 2025
Our paper, “Relationships and Characteristics of Self-Organized Vehicle Groups and Other Remaining Vehicles in Disordered Heterogeneous Traffic,” has been published in Collective Dynamics.
In this study, we investigated the differences and relationships between vehicle groups that travel together (Groups) and randomly moving vehicles in chaotic, heterogeneous traffic environments such as those seen in developing countries, mainly using indicators from graph theory.
The results suggest that typical traffic formations in developing countries consist of Groups surrounded by freely moving vehicles. Furthermore, even among vehicles that appeared to move randomly, we found that certain types tend to occupy positions more susceptible to acceleration and deceleration influences.
You can read the paper here: Link to published ver.
March 13, 2025
We held a “Thank you, M2/B4 & Welcome, new B4 students” gathering!
Let’s continue to make steady progress in our research in the coming academic year. ◎
February 2025
The M2 midterm presentations and B4 final thesis presentations were successfully completed!
Everyone’s presentation skills have definitely improved. Great work, everyone!
December 17, 2024
We held our year-end party in a hybrid style (both in-person and online)!
December 2–5, 2024
We gave four presentations at the international conference Traffic and Granular Flow, held in Lyon, France.
November 1, 2024
Thank you very much for visiting our lab during the lab. introduction session and the social gathering afterward!
We also appreciate the many students who visited our lab in the following days.
September 29–30, 2024. Our lab went on a trip to Kusatsu Onsen. We enjoyed the famous hot springs along with yumomi (traditional water-stirring) and the Kusatsu-bushi folk song.
September 27, 2024. A B4 student successfully completed his midterm presentations of his graduate studies! We were able to receive thought-provoking questions from the professors. Let's keep up the good work!
July 14, 2024. We had many visitors at our Open Campus. Thank you for your participation!
July 7-13, 2024. Traffic video observation and bus and signal observation were conducted in Ulaanbaatar, Mongolia!
July 4, 2024. Nagahama gave a lecture at Kindai University.
May 21, 2024. A yakitori party was held!
April 2, 2024. The new academic year kicked off with a new B4 student!
February 9, 2024. B4 student has successfully completed his graduate research presentations! In addition to significant research, the presentation was well refined. Good job!
February 6, 2024. Pizza seminar was held after the final practice for the thesis presentation.
December 1, 2023. Nagahama has been invited to give a talk at The Mathematical Society of TrafficFlow.
http://traffic.phys.cs.is.nagoya-u.ac.jp/~mstf/index.html
November 26, 2023 We had many visitors at our open campus. Thank you very much!
After that, we held a sushi seminar:)
October 28-29, 2023. We went camping in Susono for a lab trip. There was a thunderstorm at midnight, but we enjoyed hot spring and BBQ!
September 26, 2023, B4 Supervisory Student, Mr. Nicika Asai presented "Effects of the Ratio of Respective Vehicle Types in Mixed Traffic on Traffic Flow" at the Interim Graduation Research Presentation of our Management Science and Social Informatics Program.
Good work!
September 25, 2023, The paper "Potential risk of driving performance under combined conditions of taking second-generation antihistamines and attending calls using a hands-free function" was accepted for publication in Traffic Injury Prevention.
This research is based on an academic collaboration agreement between Hoshi University and the University of Electro-Communications.
September 19, 2023, we hosted the first "Seminar on Heterosocial Systems" and invited Dr. Jia Xiaolu.
Dr. Xiaolu Jia introduced the discrepancy between physical and subjective congestion observed in pedestrian traffic flow with various attributes.
Thank you very much for your lecture!
Seminar website: https://sites.google.com/view/heterosocialsys-seminar/home
September 9, 2023, Nagahama presented "Research on chaotic vehicular traffic-perspectives of data science, physics, and traffic engineering-" at the 10th UEC Seminar in ASEAN.
Nagahama introduced various approaches of research on traffic in developing countries to ASEAN researchers/students with various research backgrounds.
September 9, 2023, article "Learning and predicting the unknown class using evidential deep learning" was published in Scientific Reports.
Access to printed ver.: https://www.nature.com/articles/s41598-023-40649-w
June 23, 2023 "Optimizing Evidential Deep Learning Generators for Modeling Vehicular Traffic Patterns in Developing Countries" was presented at the International Symposium on Scheduling 2023.
Algorithms for generating various types of vehicles in a traffic simulator for the mixed traffic were studied. By generating vehicles based on real traffic trends, we aim to reproduce physical phenomena unique to mixed traffic that cannot be analyzed with macroscopic traffic simulators.
June 23, 2023, Mr. Seigo Takahashi, a master's student with whom we are collaborating, presented "Effect of Supplier Selection of Electric Moped Scooters Sharing Services for Material-Based Greenhouse Gas Emissions and Costs" at International Symposium on Scheduling 2023.
This presentation received The Encouragement Award in International Symposium on Scheduling for this presentation. Congratulations!
March 2023, Ms. Shiori Fujimatsu, a supervised student, received the Megurokai Award for her bachelor thesis.
This research examined road surface design that suppresses driving speed not in a single landscape environment, but in a variety of landscapes or changing landscapes.
Congraturations!
December 9, 2022 A supervised student gave a poster presentation at The 4th ASEAN - UEC Workshop on Informatics and Engineering.
In order to avoid "inappropriate system use based on distrust" in automated systems, we measured the effects of additional information presentation and an interface for pointing out system malfunctions on the sense of trust. In particular, this study focused on automated driving and driver assistance, and found that information presentation and interfaces increase trust.
December 9, 2022 Poster presentation at The 4th ASEAN - UEC Workshop on Informatics and Engineering.
In road traffic in emerging countries, multiple vehicles have relations through acceleration and deceleration. In this study, we analyzed such relations or connections between "randomized and grouped vehicles" based on graph theory, and suggested that the connection between these areas might be weak.
I was invited to give an invited lecture at Traffic and Granular Flow 2022 (IIT Delhi) on October 16, 2022.
I discussed the significance of studying road traffic in emerging countries, where a variety of vehicles are moving in all directions, in relation to the maintenance of diversity in society.
Conference website
https://tgf.iitd.ac.in/index.html
Oral presentation at Traffic and Granular Flow 2022 (IIT Delhi), October 16, 2022.
This research evaluated a prototype vehicle generation algorithm used to simulate emerging road traffic.
By modifying a vehicle generation model, we aim to elucidate the behavior of emerging road traffic more accurately.
Conference website
https://tgf.iitd.ac.in/index.html
June 8, 2022 Poster presentation at 2022 IEEE Conference on Cognitive and Computational Aspects of Situation Management.
This is a pilot study of the effects of the urban road environment (especially scattered garbage and blaring horns) on driving behavior.
Conference website
https://edas.info/web/cogsima2022/home.html
The link to the Accepted ver. is in "Papers, etc.: Publications".
May 13, 2022 A press release on the joint research on congestion felt by pedestrians has been posted on the following website.
University of Tokyo Press Release (UTokyo Focus, English)
https://www.u-tokyo.ac.jp/focus/en/press/z0508_00219.html#
The University of Electro-Communications Press Release
(English) https://www.uec.ac.jp/eng/news/announcement/2022/20220513_4481.html
May 12, 2022 A joint research paper on congestion as perceived by pedestrians has been published in Transportation Research Part F: Traffic Psychology and Behaviour.
Article URL: https://doi.org/10.1016/j.trf.2022.04.007