With the techniques of wireless communications growing mature, Inter-Vehicle Communications provide an efficient way to improve traffic safety and prevent congestion through exchanging or disseminating the traffic information. Broadcast techniques are usually applied for delivering the emergency messages to drivers but often influenced by the hidden terminal, interference, and contention problems. The paper proposes a new broadcast algorithm which is an event-driven protocol and suitable for cooperative collision avoidance in two-way multi-lane highway. Its message-relaying decisions are made in receiver based on the position, direction, and velocity properties of transmitting and receiving vehicles. The simulation results show that the proposed algorithm delivers the emergency messages efficiently and it has the lower latency and less retransmission than other flooding based protocols.