Traffic Signal Timing Centre & Green-Wave Network

🤖 AI-generated summary of the sources below · 🔎 Last verified 2026-08-06

This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

How this atlas is made · What “last verified” means

Nanjing's traffic police run a dedicated signal timing centre for the main urban area, staffed jointly by officers, traffic engineers from the local supplier Nanjing Les and academics from Southeast University's transport school. Its working method is unusual for a police unit: large-scale floating-car trajectory data collected by Didi is combined with the force's own loop and video detectors to rank junctions by service level, and candidate problems are verified on the video wall before a timing plan is changed. The output is a coordinated green-wave network layered over the city's arterials, with day-part plans per junction rather than a single fixed cycle.

Live 📅 since 2019 🤖 Uses AI

Outcome🔄 Ongoing

Evidence🏛️ Official

Run byNanjing Public Security Bureau Traffic Management Bureau (南京市公安局交通管理局), signal timing centre

Scale🏙️ City-wide

📊 Impact

When the programme was reported in 2018 the network had reached 154 green-wave corridors covering 1,080 junctions, and the traffic police put average speeds on Zhongshan East Road, Beijing East Road and Hanzhong Road up 15%, with the northbound-to-southbound stretch of Jiangdong Middle Road up 53%.

🎓 Lesson

Two things are worth separating here. Buying a commercial mobility dataset gives a signals team something almost no city measures for itself — turn-by-turn delay on every approach — but it also makes the operator's performance evidence dependent on a private firm's data licence. And the newer claim, that an adaptive control system now covers every main-urban junction and put Nanjing first nationally on two congestion indices, exists only in the supplier's own marketing.

🚲 Mobility Traffic management Sensors & IoT Artificial intelligence

Sources

↗ Modern Express / ZAKER Nanjing via China Jiangsu (media)10 Oct 2018. Source of the network size and the speed figures: 『南京绿波带已达154条，串联起1080个路口』; 『中山东路、北京东路、汉中路等路平均车速仍提高15%』; 『江东中路（汉中门大街至江山大街段）北向南甚至提高了53%』. These are traffic-police figures reported by media, not an independent evaluation.

↗ Industry case study on the timing centre, reproduced on Sohu (trade press)7 Dec 2021. Source for staffing and method: 『配时中心团队由支队民警、南京莱斯的交通工程师以及东南大学交通学院的专家共同组成』 and 『利用滴滴所采集到的大规模浮动车轨迹数据结合南京交警自有检测器数据判断各个交叉口交通服务水平和交通信号问题，同时通过视频监控平台进行验证』. Contains no junction counts or measured effects.

↗ Nanjing traffic police talk, Saiwen Traffic (trade press)Talk by Nanjing traffic police officer Su Ziyi on building and running the signal timing centre. LIMITATION: the article body sits behind a login wall and could not be loaded. The September 2019 founding date used for yearStart comes from the indexed abstract of this piece and has not been verified against the full text — treat it as the weakest fact in this entry.

↗ Nanjing Les Information / vendor release via Sohu (vendor PR)29 Apr 2026, timed to a trade fair. Claims the adaptive control system was rolled out from March 2025 and completed across 『主城区全量路口』 by the end of 2025, and that Nanjing ranked first nationally on two Amap 2025 indices (『高延时拥堵路口占比』, 『路口时段方案匹配度』). Supplier marketing; used only as an attributed claim, never as an impact figure.

Continue exploring

Compare this project

🇦🇺 SCATS — Sydney Coordinated Adaptive Traffic System · Sydney Adaptive control from detectors since 1975, against a centre that ranks junctions from ride-hailing traces before touching a plan. 🇮🇳 Bengaluru Adaptive Traffic Control System · Bengaluru Both retimed arterials and published speed gains; only one of them also published the citywide speed that fell anyway. 🇨🇴 SIMM Intelligent Mobility System & Traffic Control Center · Medellín Police-run rooms where people still decide: Medellín reroutes manually, Nanjing verifies on the video wall before changing a plan.

Explore the wider context

🚦 Asphalt or algorithms 🚦 Traffic management guide 🏙️ Nanjing city profile 🚲 Mobility projects 📖 Adaptive traffic signals 📖 Automated speed enforcement (speed cameras)📖 ANPR (automatic number-plate recognition)

📎 Cite this project

1001 Smart Cities (2026). “Traffic Signal Timing Centre & Green-Wave Network” — Nanjing, China. The Smart City Atlas. https://1001smartcities.org/projects/nanjing-signal-timing-centre/ (last verified 2026-08-06). Data: CC BY 4.0.

The underlying data is free to reuse with attribution — see the open data page.

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