The net revenues received by a taxing entity shall be expended only for the following:

1. (a) The planning, construction, and maintenance of, and the acquisition of rights-of-way for, exclusive public mass transit guideways and exclusive bus lanes and related fixed facilities to such guideways and bus lanes.
2. (b) The purchase of transit vehicles.
3. (c) The payment of principal and interest on voter-approved bonds issued for the purposes specified in subdivision (a) or (b).