A vehicular network topology changes rapidly due to the high mobility of network nodes. This network is formed spontaneously to support high speed and guaranteed communications, which in turn makes the delivery of emergency warning packets (EWPs) through dynamic routing protocols not guaranteed and unreliable. Hence, we propose a broadcast scheme through which the EWPs in the ad hoc part in client-server ad-hoc (CSAH) communication platform (H. Alshaer and E. Horlait, 2004) are transmitted from an abnormal vehicle to others in its zone. This broadcast scheme is efficient since it delivers rapidly the EWPs, and it is adaptive since the rebroadcast probability of a vehicle node changes dynamically in term of the number of vehicle nodes in its zone. Consequently, this broadcast scheme alleviates the problem of the simple flooding broadcast which is referred to broadcast storm and represented by packets redundancy, contention, and collision in the network.