When the number of automated vehicles deployed in public traffic reaches a significant level, their form of interaction with other automated vehicles, human controlled vehicles and non-motorized participants will impact traffic overall safety and efficiency. While many studies have approached impact analysis on the side of efficiency and via simulation, we here elaborate on practically applicable methods for safe cooperation of automated vehicles from the perspective of life-size experimental platforms. The EU project UnCoVerCPS investigates on-line verification based safety analysis and control of cyberphysical system, applying the developed techniques to cooperation of automated vehicles. In a previous publication, a message set for negotiation of such a cooperation has been proposed, (STRP), which is compatible with the investigated verification approach. This publication follows up by providing results and analysis of test drives with two cooperating, automated vehicles with differing software and hardware architectures. The STRP messages are employed to negotiate a cooperative lane change via Car-to-Car radio in an urban scenario with non-trivial road-geometry. The applicability of the distributed cooperation scheme to real-world conditions is demonstrated.