Junyi Ji 🌱's Avatar

Junyi Ji 🌱

@jijunyi

Enjoy transportation and dynamic systems. Open Traffic Science. Views are my own.

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07.01.2025
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Latest posts by Junyi Ji 🌱 @jijunyi

We write because we want the knowledge to be recorded!

03.11.2025 02:28 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

One of the reasons I think quality matters is that when I read those high-quality papers written decades ago, I really learn a lot. You can clearly see the time and effort devoted to every one.

03.11.2025 02:28 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

When I see posts claiming 15 or 20 papers for presentation at the TRB Annual Meeting, the peer pressure is undeniable. It's easy to get caught up in the race for quantity.

But it begs the question: At what cost to quality?

03.11.2025 02:24 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

We may need tell the world a message: don't dream of RL for real-time signal control (in practice)! Multiple reasons...

26.10.2025 05:34 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Safety Perspective on Assisted Lane Changes: Insights from Open-Road, Live-Traffic Experiments This study investigates the assisted lane change functionality of five different vehicles equipped with advanced driver assistance systems (ADAS). The goal is to examine novel, under-researched featur...

Preliminary findings from the field experiments (conducted jointly with and led by JRC colleagues) on commercial L2+ automated vehicles show that their lane-changing behavior is surprisingly consistent.

08.10.2025 23:53 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Questioning fundamental traffic flow theory assumption
Questioning fundamental traffic flow theory assumption YouTube video by Ammar Dado

I highly recommend Prof. Benn Coifman’s talk. When discussing the fundamental relationship in traffic dynamics, let's first check how the data is generated.

youtu.be/4oZM68VEkfE?...

08.10.2025 23:49 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Back in 2015 (as an undergrad), I felt long-horizon traffic planning would not be the priority, we needed fine-grained, high-resolution data and research. Now, 10 years later, enabled by GenAI, we can finally move from coarse minute-level analysis down to the second level.

tinyurl.com/trafficwavex

08.10.2025 23:45 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Scalable analysis of stop-and-go waves: Representation, measurements and insights Analyzing stop-and-go waves at the scale of miles and hours of data is an emerging challenge in traffic research. The past 5 years have seen an explosion in the availability of large-scale traffic dat...

After two years of effort, this study has now been accepted through peer review. In nowdays era of massive vehicle trajectory data, it is time to revisit how we analyze and understand traffic waves. I created a gallery with hundreds of traffic waves: trafficwaves.github.io.

arxiv.org/abs/2409.00326

08.10.2025 23:36 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Rethinking the Sioux Falls Network: Insights from Path-Driven Higher-Order Network Analysis Benchmark scenarios are widely used in transportation research to evaluate routing algorithms, simulate infrastructure interventions, and test new technologies under controlled conditions. However, th...

I really enjoyed this paper, although I’m an outsider to Transportation Network Modeling. My main takeaway is clear: as more data becomes available, we should advance toward analyzing more complex networks, rather than continuing to benchmark solely on Sioux Falls.

arxiv.org/abs/2508.06234

08.10.2025 23:34 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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It's great that we can post dataset and code link in the paper article info now!

16.09.2025 01:51 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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I'm always amazed by traffic research history. This is a highway test track at Ohio State University in 1969.

10.08.2025 12:18 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Don't chase for buzzword! First principle matters.

04.08.2025 16:38 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I think all the top journals/conferences can consider limiting the submissions per year.

13.07.2025 15:35 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Transportation is an application-driven field. Follow the first principle and solve the problems. We don't need more problems but we need more problem-solvers.

13.07.2025 15:33 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
awesome-rerite Awesome open datasets and benchmarks in transportation research

www.rerite.org/awesome-reri...

07.07.2025 16:22 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Trajectory Data Camp at ITSC 2025 | I-24 MOTION Testbed for traffic management and automated vehicle technologiesLocated on 4 miles of Interstate 24 in Middle Tennessee

Our 2nd Trajectory Data Camp at ITSC 2025! This year’s focus is on safety and human factors, and I wish to help drive the Vision Zero moonshot.

04.07.2025 20:15 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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All the traffic scientists working on trajectory data should consider visiting this site when stopping by SF.

14.06.2025 18:40 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Legacy NGSIM I-80 is now so real in Google Maps 3D view!!!

14.06.2025 18:33 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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I have to say, TRB is where I truly grew as a researcher.

03.06.2025 17:24 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I’ll be at the TRB DATA conference as well! Just to mention, my advisor Dan Work has been my long-time supporter on reproducible research. And we’re actively contributing to open data in traffic science.

26.05.2025 19:08 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Flyer announcing Prof. Cathy Wu from MIT presenting at the TRB Conference on Data and AI for Transportation Advancement. Two sessions are highlighted: one on May 28 about accelerating transportation research transparency practices, and another on May 29 about mitigating metropolitan carbon emissions using dynamic eco-driving.

Flyer announcing Prof. Cathy Wu from MIT presenting at the TRB Conference on Data and AI for Transportation Advancement. Two sessions are highlighted: one on May 28 about accelerating transportation research transparency practices, and another on May 29 about mitigating metropolitan carbon emissions using dynamic eco-driving.

πŸ“£ I will be giving two talks this week at the TRB DATA conference in Seattle, which explores the intersection of transportation, artificial Intelligence, and data analysis. I love these practitioner + researcher conferences. πŸ€–πŸ§ πŸ‘‡

26.05.2025 18:02 πŸ‘ 6 πŸ” 4 πŸ’¬ 1 πŸ“Œ 2
Flyer announcing a presentation at the Transportation Research Symposium 2025, scheduled for Monday, May 26, 13:15-15:15 in Rotterdam, The Netherlands. Session topic is 'Traffic control in the era of new technologies,' with the presentation titled 'Towards Accelerating Transportation Research: Measuring the State of Transparency Practices.' Multiple authors from various international institutions are listed, including Ruth Lu, an undergraduate researcher at MIT, whose photo is featured prominently. A QR code and the website rerite.org are displayed in the upper right corner. The flyer background is orange with black and white text.

Flyer announcing a presentation at the Transportation Research Symposium 2025, scheduled for Monday, May 26, 13:15-15:15 in Rotterdam, The Netherlands. Session topic is 'Traffic control in the era of new technologies,' with the presentation titled 'Towards Accelerating Transportation Research: Measuring the State of Transparency Practices.' Multiple authors from various international institutions are listed, including Ruth Lu, an undergraduate researcher at MIT, whose photo is featured prominently. A QR code and the website rerite.org are displayed in the upper right corner. The flyer background is orange with black and white text.

πŸ“£ #RERITE 's first conference presentation will take place tomorrow at the Transportation Research Symposium at Rotterdam in The Netherlands! πŸš‚πŸ›£οΈ

We use Large Language Models (LLMs) to measure the state of data & code availability in transportation research. Join to learn: πŸ‘‡

25.05.2025 21:35 πŸ‘ 5 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0

Speed depends on size
Balanced by dispersion
Oh, solitary splendor.

19.05.2025 18:00 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Peter Lax, Pre-eminent Cold War Mathematician, Dies at 99

In memory of Peter Lax (1926–2025).
I will dedicate myself to advancing the next chapter in the applications of hyperbolic partial differential equations in traffic flow dynamics.
www.nytimes.com/2025/05/16/s...

17.05.2025 20:51 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Interesting! This is my hometown.

17.05.2025 20:41 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

You can be sad but please never be discouraged.

10.05.2025 19:45 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Our student team awarded Lacy-Fischer Interdisciplinary research grant on freeway safety

My first research grant!

04.05.2025 22:26 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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At the end of a paper [1] by Newell: Will we better in the next 50 years?

[1] Newell, Gordon F. "Memoirs on highway traffic flow theory in the 1950s." Operations Research 50, no. 1 (2002): 173-178.

02.05.2025 23:55 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

🚦Inaugural Steering Committee of #RERITE 🚦

Dr. @cathywu.bsky.social
Dr. Xuesong (Simon) Zhou & Dr. Bidisha Ghosh
Dr. Silvia Francesca Varotto & Dr. Bahman Madadi
Dr. Yanbing Wang
Dr. Michalis Makridis

🌐 www.rerite.org
πŸ”— lnkd.in/d38VqpdM

#OpenScience #Reproducibility #Transportation

11.04.2025 13:40 πŸ‘ 4 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Imaging that we have a perfect, well-calibrated car-following model, what's the best thing you can do with it?

12.04.2025 21:17 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0