The director of transportation shall annually make a report to the general assembly, during the month of January, setting forth in detail all its transactions during the preceding year and making such recommendations for improving the main highways of the state as the director shall deem necessary for the best interests of the entire state, having regard also to the connection of the main highways with the main highways of the adjoining states. No work, other than preliminary surveys, shall be done upon any of the main highways previous to the time that the main highways are made a part of the state highway system and money appropriated for their improvement. The director shall direct and control, according to law, the expenditure of all appropriations and upon the director’s request the department of administration is hereby authorized to make all contracts necessary for that purpose.