(a) Route 49 is from:
(1) Route 41 near Oakhurst to Route 140 at Mariposa.
(2) Route 140 at Mariposa to Route 120 near Moccasin.
(3) Route 120 near Chinese Camp to Route 80 near Auburn via the vicinity of Sonora; via Angels Camp, San Andreas, and Jackson; and via the vicinity of El Dorado, Diamond Springs, and Placerville.
(4) Route 80 near Auburn to Route 20 in Grass Valley.
(5) Route 20 at Nevada City to Route 89 near Sattley via Downieville.
(6) Route 89 near Sierraville to Route 70 near Vinton via Loyalton.
(b) (1) The commission may relinquish to the City of Auburn the portion of Route 49 that is located within the city limits of that city, upon terms and conditions the commission finds to be in the best interests of the state, if the department and the city enter into an agreement providing for that relinquishment.
(2) A relinquishment under this subdivision shall become effective immediately following the county recorder’s recordation of the relinquishment resolution containing the commission’s approval of the terms and conditions of the relinquishment.
(3) On and after the effective date of the relinquishment, the relinquished portion of Route 49 shall cease to be a state highway.
(4) The portion of Route 49 relinquished under this subdivision shall be ineligible for future adoption under Section 81.
(5) For the portion of Route 49 that is relinquished under this subdivision, the City of Auburn shall maintain within its jurisdiction, signs directing motorists to the continuation of Route 49. The city may apply to the department for approval of a business route designation in accordance with Chapter 20, Topic 21, of the Highway Design Manual.