You'd think that, because of decades of government propaganda, but several years back when Montana eliminated their interstate speed limits, traffic fatalities decreased.
The biggest problems with speed limits is that too many of them are artificially low. People know how fast a safe speed is without nanny telling them what it is.
I agree that artificially lowering the speed can actually contribute to accidents because when it’s too low, people tend to get bored and want to be distracted.