A safety bumper assembly for a vehicle shutting off a vehicle engine when the vehicle hits an obstacle, particularly an autonomous vehicle used for agricultural purposes. The assembly includes bumper shafts holding a bumper bar at a distance from a support structure of the vehicle and shuts off the vehicle engine in such fashion that the vehicle comes to a full stop before the bumper has reached its most inward position closer to the vehicle body. A vehicle equipped with the safety bumper assembly has vehicle frame integrating a support structure of the safety bumper assembly.