31-7-1 Definition of terms. 31-7-2 Employment of personnel--Contracts in behalf of state--General powers of department. 31-7-3 Cooperation with federal highway administration in location and construction of interstate highways. 31-7-4 Location and alignment of interstate highways. 31-7-5 Acquisition of right-of-way, land, and materials. 31-7-6 Points of ingress and egress--Establishment and control. 31-7-7 Grade separations at intersections with other roads. 31-7-8 Control areas and points--Programming to permit use of new construction. 31-7-9 Marking of highways. 31-7-10 State highway funds used for construction. 31-7-11 Maintenance expenses--Sources of payment. 31-7-12 Expenditures segregated in annual report. 31-7-13 Local service roads--Maintenance by political subdivisions. 31-7-14 Trunk highway system unaffected. 31-7-15 Camping prohibited at rest areas on interstate system--Petty offense. 31-7-16 Activities constituting unlawful camping. 31-7-17 Temporary rest stops permitted--Time limit. 31-7-18 Additional fine for unlawful camping--Cost of repairs.