In some places, that's how speed limits are fixed.

In Texas, for example, they do a traffic study and set the limit to the 85th percentile speed.

https://www.txdot.gov/safety/driving-laws/speed-limits/speed...

That … is definitely not how things work in the US. Municipalities set speed limits based on a variety of things including but not limited to maximizing revenue, the streets city council members live on, random news reports about speeds in adjacent jurisdictions, and so on.

Were a car to refuse to exceed the speed limit, it would be dangerously slow almost everywhere in the united states, arguably reducing safety substantially.

Reminds me show Upload, there cars had settings of how much pedestrians are respected.