Canada

The problem is that people are AWFUL at evaluating their own risk when driving, and drive at speeds that ARENT safe. Look at how few people leave appropruate stopping distances between vehicles, which is the #1 factor in preventing accidents.

The methods you proposed would likely decrease the speed vehicles travel at (ie from 80 to 60) because drivers feel like they can't travel at that speed, but the road likely still isn't safe for vehicles to travel at 60 when its that narrow.

Speed cameras catch everyone speeding, 24/7, and are the single best, economical, way to eliminate speeding from a road. Cop can't pull over every vehicle going 80 on a 4 lane road rated for 60, but the camera can ticket them all.

For sure, promote a narrower road, encourage MUP over sidewalks, and encourage safer driving when you talk to your councilors, but road reconstruction happens, generally, once every 25-50yrs. We can't wait for that timeframe to fix these problems.