In the recent years Vehicular Ad hoc Networks (VANET) became one of the most challenging research area in the field of Mobile Ad hoc Networks (MANET). Vehicles in VANET send emergency and safety periodic messages through one control channel having a limited bandwidth, which causes a growing collision to the channel especially in dense traffic situations. In this paper a protocol Particle swarm optimization Beacon Power Control (PBPC) is proposed, which makes dynamic transmission power control to adjust the transmission power of the safety periodic messages that have been aggressively sent by all vehicles on the road 10 times per a second, the proposed protocol aims to decrease the packet collision resulted from periodic safety messages, which leads to control the load on the channel while ensuring a high probability of message reception within the safety distance of the sender vehicle.