If you think this poses an immediate danger, between 8am and 4pm call Traffic Engineering at (608) 266-4767. At other times, call 911. For less urgent problems (e.g. a loop detector that doesn’t detect you on a bike), use the Report-a-Problem website. You can use the Street Signs or the Bikeway Concerns categories. The latter lets you upload a picture, which sometimes makes for a more effective report.