With respect to roads or portions thereof, the Department shall determine which if any, shall be improved and which, if any, shall be added to the state highway system.
29 Del. Laws, c. 63; 34 Del. Laws, c. 81; Code 1935, § 5724; 17 Del. C. 1953, § 133; 53 Del. Laws, c. 39, § 7; 57 Del. Laws, c. 671, § 1G.