Vehicles suddenly exiting road-side parking constitute a hazardous situation for vehicle drivers as well as for Connected and Autonomous Vehicles (CAV). In order to improve the awareness of road users, we propose an original cooperative information system based on image processing to monitor vehicles parked on the road-side and on communication for sending early warning to vehicles on the road about vehicles leaving their parking space. We have implemented and tested this system in two places in France with parallel and perpendicular parking slots for several camera positions, and we report on its efficiency and its limits.