Taisei and TIER IV test three self-driving cars in a tunnel for Japan's MLIT

Taisei and TIER IV test three self-driving cars in a tunnel for Japan's MLIT

14 October 2026: Japan's Ministry of Land, Infrastructure, Transport and Tourism has selected Taisei Corporation, TIER IV and Taisei Rotec for a demonstration meant to speed up deployment of the Autoflow Road. The trial runs for eight days in late October and early November 2026, using three experimental autonomous vehicles in a full-scale tunnel.

What the Autoflow Road is

The ministry promotes the Autoflow Road as a logistics system that moves cargo with unmanned, automated vehicles in dedicated logistics lanes. The 2026 demonstration is aimed at making deployment lean and scalable.

Where and with what

The test takes place at the full-scale tunnel test facility and test track, using the east straight section and the south loop, operated by the ministry's National Institute for Land and Infrastructure Management. The routes include straight and curved sections, and the driving space is tested at standard, intermediate and minimum widths.

The three vehicles are based on passenger cars and are for testing only, not the final dedicated transport hardware. They run Pilot.Auto, TIER IV's driving software, which is built on the open-source Autoware.

What gets tested

Multi-vehicle operation is the theme: platooning, bidirectional driving, lane changes, merging and diverging, and obstacle avoidance. The team will verify following, stopping, passing oncoming vehicles, merging and diverging, obstacle avoidance and berth stopping accuracy.

Three further goals are listed. The first is to simplify the sensors on the vehicles and the roadside infrastructure needed for a dedicated lane. The second is to validate Taisei's T-Localizer, a self-localisation support technology. The third is to assess how well Pilot.Auto adapts and scales for logistics work.

Who does what

Taisei handles overall planning and execution, verification of T-Localizer and the infrastructure simplification, and data analysis. TIER IV provides the vehicles and the driving system, runs the test drives, and collects and analyses driving data. Taisei Rotec plans and builds the reflector installation, takes measurements and gives field support.

Earlier results and tunnel technology

The same companies took part in a ministry demonstration in fiscal 2025, using a TIER IV vehicle, T-Localizer and T-iPower Road, Taisei's dynamic wireless power transfer system. The results indicated potential applicability and feasibility for the Autoflow Road, and also identified operational challenges.

Taisei developed T-Localizer and T-iPower Road; the first helps a vehicle locate itself, the second transfers power wirelessly to vehicles while they drive. TIER IV builds its autonomous driving services and products around Autoware, among them Pilot.Auto, Web.Auto and Edge.Auto. Taisei Rotec has developed tunnel surface coatings intended to improve vehicle LiDAR perception in places where GPS does not work, such as tunnels. The release says insights from the project will help clarify the respective roles of vehicle autonomy and road infrastructure.

A footnote in the release states, "Passenger-car-based vehicles will be used in this demonstration for testing purposes." The plans described are based on those currently submitted to the ministry.

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Sources

• TIER IV: TIER IV advances Autoflow Road deployment with Taisei and Taisei Rotec, 14 October 2026