Section 68-2237 - Nonconforming signs(a) Any sign lawfully in existence along the interstate system or the federal aid primary system which is not located in a business area and which is not in conformity with the provisions of this act shall not be required to be removed until March 31, 1974. Any other sign which is lawfully erected but which does not conform to this act by reason of a highway being made a part of the federal aid primary or interstate highway system subsequent to March 31, 1972, shall not be required to be removed until the end of the fifth year after it becomes nonconforming.(b) Notwithstanding any other provisions of this act, the standards prescribed by this act concerning the size, lighting or spacing of signs permitted in business areas shall apply only to those signs erected subsequent to March 31, 1972.L. 1972, ch. 251, § 7; March 31.