  Multi-Target Multi-Camera Tracking has a wide range of applications and is
the basis for many advanced inferences and predictions. This paper describes
our solution to the Track 3 multi-camera vehicle tracking task in 2021 AI City
Challenge (AICITY21). This paper proposes a multi-target multi-camera vehicle
tracking framework guided by the crossroad zones. The framework includes: (1)
Use mature detection and vehicle re-identification models to extract targets
and appearance features. (2) Use modified JDETracker (without detection module)
to track single-camera vehicles and generate single-camera tracklets. (3)
According to the characteristics of the crossroad, the Tracklet Filter Strategy
and the Direction Based Temporal Mask are proposed. (4) Propose Sub-clustering
in Adjacent Cameras for multi-camera tracklets matching. Through the above
techniques, our method obtained an IDF1 score of 0.8095, ranking first on the
leaderboard. The code have released: https://github.com/LCFractal/AIC21-MTMC.
