Sec. 2. When used in this chapter, the term:
(a) "Utility" shall include all privately, municipally, publicly, or cooperatively owned systems for supplying communications, power, light, heat, electricity, gas, water, pipeline, sewer, sewage disposal, drain, or like service, directly or indirectly, to the public.
(b) "Cost of relocation" shall include the entire amount paid by a utility properly attributable to such relocation, after deducting therefrom any increase in the value of the new facility and any salvage value derived from the old facility.
(c) "Highway" when used in this chapter shall mean only those routes which are included within the national system of interstate and defense highways.