These arrangements provide opportunities to combine the development, financing, and/or operation of facilities that serve more than one transportation mode, including highway, transit, rail, and airports. Multimodal partnership projects do not have to be PPPs. However, the opportunities for private sector involvement in multimodal partnerships are an area of potential growth for transit-related PPPs, particularly when toll roads and airports are involved due to the ability to leverage toll revenues and airport passenger facility charges for transportation investments.