You can put all the speed limit signs you want on that street, but it doesn't change the fact that the road is too wide and straight and people will go the spee

You can put all the speed limit signs you want on that street, but it doesn't change the fact that the road is too wide and straight and people will go the speed they feel comfortable at, regardless of the signs. That street needs to be narrowed, have parked cars on the side, have speed tables, a boulevard, dynamic feedback signs, or other traffic calming measures. Physical objects and changes to the environment are what cause drivers to slow down in urban environments, not flimsy metal signs. There have been numerous studies and research projects on this. Here's one by the Federal Highway Administration showing the effects of various traffic calming techniques in situations just like this one: https://www.fhwa.dot.gov/publications/research/safety/08067/ https://www.fhwa.dot.gov/publications/research/safety/08067/