An agreement where one or more public transit agencies or governmental units contribute to, or are assessed for, the value of public transit services provided by another public transit agency. There is usually a written Memorandum of Understanding or mutual agreement on the calculation and payment for the services. Generally, the service is part of the public transit agency's directly operated service. The Federal Transit Administration (FTA) uses a Cooperative Agreement as the instrument by which it awards federal assistance to a recipient to support a particular project in which FTA takes an active role or retains substantial control.