Currently, there is a lack of methodological tools, based on competitive behavioral models, available to support decision makers with regard to encouraging the use of green vehicles. This paper is devoted to the problem of competitive traffic flow assignment in a green transit network consisting of green and nongreen routes. The analysis of a competitive framework is performed, and an approach for defining Nash equilibrium assignment in a green subnetwork is developed. The conditions of an optimal green transit network are also defined explicitly for a network of parallel routes.