シグナル・ジレンマ

シグナル・ジレンマ (SIGNAL DILEMMA) is a free 3D traffic simulation game for the browser. You are MICHI, a city's traffic-control AI, switching which direction gets green at the intersections of a small diorama town with left-hand traffic, horizontal traffic lights and utility poles, to keep cars, buses and pedestrians moving. Each switch passes through amber and all-red, so it takes a few seconds; drivers and pedestrians kept waiting lower a satisfaction meter, and if it reaches zero the AI is shut down. From Monday to Friday the town grows from one intersection to nine, with a rainy day, a crash and a fireworks night with a scramble crossing; ambulances and fire engines follow red dotted routes you can clear ahead of time, and pedestrians who wait too long cross on red. Each day also brings a request with no right answer, such as a cat asleep in the crossing, a company offering money for green lights, a police officer asking for camera feeds without a warrant, the mayor's motorcade or a crash log you could quietly edit; your answers shift four values (compassion, fairness, honesty and efficiency) and lead to one of eight endings. Between days you can buy upgrades such as vehicle sensors, and when you retry a day after a shutdown you can spend budget on TSUJI, a helper AI that takes over one intersection. It plays with mouse, keyboard, gamepad or touch, in Japanese or English. MICHI and TSUJI are characters run by the game's own rules, not by an AI service. The README credits planning and direction to the developer, たぬ (tanuu5), and development to Claude Code (Claude Opus 5.5, reasoning level MAX). Buildings, vehicles, signals, music and sound effects are all generated in code, with no image or audio files. Free on the developer's GitHub Pages site; the code is MIT-licensed.