A method and a system determine track availability. The system is configured to be fitted to a guided vehicle liable to move downstream on a track. The system contains at least one camera able to capture images of a downstream section of track. The downstream section being a track portion extending from a first point of the track located downstream of the guided vehicle to a second point of the track located downstream of the guided vehicle. The distance separating the camera from the second point is being greater than the distance separating it from the first point. At least one image processing and analysis device is provided and is able to analyze each image taken by each camera, to locate the downstream section therein, to determine first a downstream safety distance, and second an availability state of the track between the first point and the second point.