There’s no excuse: when members of a community see a dangerous street for what it is, it shouldn’t take a death (or several deaths) for the city to finally take action.
It is similar in the UK, there are a couple of junctions on my daily commute where I see people jump red lights every single day and that have on numerous occasions put me (a cyclist) in danger because of this.
I have raised this issue and asked about the possibility of red light cameras to try and deter these idiots. I get the same response every time that they won't even consider putting in safety measures until there are multiple serious accidents caused by it.
I haven't been ignored flat out yet, to be honest I have given up trying, but depending on the respondent I have had various levels of disinterest within the responses.
Whilst fine in theory if no one is getting fines then a sign will not deter people as they will actively look for the supporting equipment as well. I also don't have the money or resources to make a convincing looking.
I'm well aware of how people act at these hot spots and so I am ever vigilant, I was more concerned about the occasional cyclist who isn't aware and often less observant due to their infrequent dealings with cunts in cars whilst on a bike.