Intelligent Transportation Systems (ITS) has two major sub-components that depend on each other namely, vehicles and infrastructure. For the whole system to perform optimally and safely, both vehicle and infrastructure sub-components of ITS should be operating without major disruptions. In this paper, we focus on the better maintenance of ITS equipment to maximize overall system performance. Long-term down time of ITS equipment due to the unavailability of spare parts will not only increase personnel and repair time requirements, costs of replacement parts but also might lead to increased delays, poor air quality and fuel consumption. Therefore, timely availability of the spare parts of essential components of ITS equipment is essential within the inspection and maintenance procedures of ITS. The proposed spare parts inventory control model in this paper can determine the optimum levels of the safety stocks under probabilistic failure and availability assumptions for components of various ITS equipment. When this inventory control model is fully integrated into Rutgers Intelligent Transportation Systems Inspection and Maintenance Software (RITSIMS) , it will allow its users to efficiently manage DOT's ITS spare parts inventory using historic maintenance and inspection data that is being collected by respective databases of RITSIMS.