They're only popular because people are routinely lied to. We see this same issue time and time again in "free markets".
If you tell people this will help stop crime and that's it, everyone and their mama is gonna say yes.
If you tell people the truth, that police don't really care to look at the data and this surveillance is going to be used to target innocent people for unrelated "crimes" on the taxpayers dollar, then everyone would say no.
This is also why 99% of surveys are broken. You can get people to agree to literally anything if you just lie a little. After all, Adolf Hitler got elected by promising to fix the German economy and, in a way, he did.
In what way are voters in these municipalities being lied to? We got logs of all the searches, and incident reports of every time they were used to curb another vehicle. We know how well they did (or didn't, in our case) worked.
I don't know what "surveys" have to do with this. Voters voted on it; it was a campaign issue in our trustee election.