Our city did a traffic survey of a local street that is the primary route for everyone going from surrounding neighborhoods to downtown and found the average speed was ~2 mph over the posted limit, with the 85th percentile at ~5 mph over the speed limit. These are reasonable speed for such a wide road. The city then added several 'safety' features to it, and found in a subsequent survey that the changes actually did little to slow traffic. One feature is a pair of speed bumps. Some drivers slow to about 5 mph to go over the bumps, increasing the risk of rear end accidents. Other drivers veer into the bike lanes to go partially around them without slowing down. Everyone else slows down a reasonable amount, but then subsequently accelerate back up to the speed limit on a block where jaywalking is common. Some of the features they added are, in my opinion, beneficial, like turning a side street into a one way road after frequent accidents from people turning left out of it.
But you can't talk about it on Nextdoor. The second you criticize the speed bumps you'll be ignored (if you're lucky) or attacked. Nuance is not allowed. You're either for all the changes, even the dangerous ones, or you're a crazy speed demon. Meanwhile, if you post about 'the children' who you are afraid for (even though no one has any evidence of a child ever being hurt by a driver on this road), you're going to get upvoted a lot within the first ten minutes.
The city spent months ripping it up and paving it nice and smooth.
Then a couple months later they put up speed bumps.
We spent a lot of money to get back to the speeds people already drove.
Their campaign was successful, in no small measure because a poll of the residents showed 95% of them opposed the repaving, and that the local paper wrote a big story about the whole affair.