Road designs play an important role as well, it's not just enforcing the law.
Some roads are going to be safer simply because drivers don't feel safe driving fast. Others are safer simply because there's less opportunities to get into a collision.
Wide street in cities encourage faster driving which doesn't really save a lot of time while making the streets more dangerous, for example.
After seeing how road design calmed traffic speeds in multiple areas in my city by reducing lanes and using medians that ‘narrow’ the apparent width of the roadway, and in some places just with road paint (it’s weird but it works).
I believe that road design is the only way to control how fast people drive. Speed limits are useless for controlling speed, people drive the speed the road is designed for.
Some roads are going to be safer simply because drivers don't feel safe driving fast. Others are safer simply because there's less opportunities to get into a collision.
Wide street in cities encourage faster driving which doesn't really save a lot of time while making the streets more dangerous, for example.