The Engineering and Public Works Department is hereby authorized to mark lanes for traffic on street pavements at those places as traffic conditions require, consistent with the Traffic Code of the city. Where traffic lanes have been marked, it shall be unlawful for the operator of any vehicle to fail or refuse to keep the vehicle within the boundaries of any lane except when lawfully passing another vehicle or preparatory to making a lawful turning movement.
(Iowa Code §§ 321.255, 372.13(4)) (1999 Code, § 61.03) Penalty, see § 10.99