The Internet of Vehicles (IoV) and vehicular clouds use sensor data and information from vehicles to implement an intelligent transportation system for future smart cities. The tremendous amount of data generated in IoV can lead to channel congestion, packet loss and delay of time-sensitive messages. This can have a serious impact on the performance of applications and services provided by a vehicular network, particularly safety applications that are time critical. As such, network congestion control is an topic in vehicular networks and various methods of controlling the message transmission rate and power have been explored to-date. In this paper we have proposed a new distributed congestion control algorithm which manipulates the transmission power based on a density estimation derived from the vehicle’s driving speed. The results indicate that the proposed approach is effective in reducing packet loss and improving the relevance of the received messages.