In CARLA through 0.9.15.2, the collision sensor mishandles some situations involving pedestrians or bicycles, in part because the collision sensor function is not exposed to the Blueprint library.
https://github.com/carla-simulator/carla/tags
https://github.com/carla-simulator/carla/pull/7445
https://github.com/carla-simulator/carla/issues/7394#issuecomment-2058130066