Tolerable standards for establishing adequacy of existing routes shall be those of the department used in highway planning, based on estimated traffic in 1975, and adequacy shall be determined by the department.
Impl. am. Acts 1959, ch. 9, § 3; Acts 1965, ch. 159, § 5; impl. am. Acts 1972, ch. 829, § 7; T.C.A., § 54-573; Acts 1981, ch. 264, § 12.