Social insects such as ants and bees perform complex tasks with pheromone communication despite lack of top-down style control. We have examined applications of this pheromone paradigm towards ITS. In this paper, a car is regarded as an insect that releases (electronic) pheromone that represents density of traffic. We propose a method to predict future traffic through a pheromone mechanism without resorting to the use of a traffic control center. We evaluate our method using a simulation based on actual traffic data and the results indicate applicability to traffic prediction. Categories and Subject Descriptors I.6.3 [Simulation and Modeling]: Applications General Terms Algorithms, Performance, Experimentation. Keywords Pheromone, traffic congestion prediction.