All tolls or other revenues received from the operation of any toll bridge or toll bridges constructed with the proceeds of bonds issued and sold hereunder shall be paid over by the department to the state treasurer. The treasurer shall deposit them forthwith as demand deposits in a depositary or depositaries authorized by law to receive deposits of state funds. The deposit shall be made to the credit of a special trust fund designated as the toll revenue fund of the particular toll bridge or toll bridges producing the tolls or revenue, which fund shall be a trust fund and shall at all times be kept segregated and set apart from all other funds.