Cooperation and information exchange will allow autonomous vehicles to increase their sensing range and maneuver coordinately, thereby greatly enhancing their safety and efficiency. The combination of autonomous driving and vehicular communications will enable Cooperative Autonomous Driving Systems (C-ADS) with stringent requirements. We present two new multi-hop forwarding algorithms specially suited to the dissemination of information in C-ADS: (i) Greedy Broadcast Forwarding, aimed to the distribution of packets within a geographical area, and (ii) Greedy Multicast Forwarding, which delivers packets only to the members of a vehicle group. A performance comparison of the proposed schemes with the broadcast forwarding algorithms defined in the ETSI GeoNetworking standard shows that Greedy Broadcast Forwarding achieves the highest reliability, while Greedy Multicast Forwarding yields the lowest traffic overhead in the considered scenario. These results indicate that the proposed forwarding algorithms are promising candidates to enable multi-hop communications in future C-ADS.