A co-operative driving system for road junctions is an example of a vehicle cyber–physical system. It integrates the cyber systems in vehicles with their physical systems to optimise co-operative driving at traffic intersections. Depending on ‘vehicle-to-everything’ technology, the system can facilitate co-operation between moving vehicles and traffic control systems, improve traffic operation and management, and help vehicles negotiate junctions safely and efficiently. To optimise the system, an improved membrane-computing-based multi-vehicle optimisation method is proposed in this paper. The method is a potential solution to the multi-vehicle optimisation problem with constrained conditions and incommensurable objectives. It can better guarantee the safety of multiple moving vehicles at a junction than several traditional multi-objective optimisation methods. Experimental analyses show how the method can reduce delays at junctions, increase junction throughput and shorten overall journey times.