(A) The Engineering and Public Works Department shall cause to be placed and maintained traffic- control devices when and as required under this Traffic Code or under state law or emergency or temporary traffic-control devices for the duration of an emergency or temporary condition as traffic conditions may require to regulate, guide or warn traffic.
(B) The Department shall keep a record of all traffic-control devices.
(Iowa Code § 321.255) (1999 Code, § 61.01)