Making drivers uneasy is often the best way to improve safety. Narrow lanes, in particular, help a good deal. https://www.wri.org/insights/bigger-isnt-always-better-narro...

Yes - the effect is seen when they improve visibility at road junctions in a effort to increase safety. Before, everyone approached the uncertain situation slowly. Afterwards, they rush head-on into collisions.

Where I live there is a stop sign before merging into a major road despite originally good visibility, so few people actually stopped, which apparently led to accidents. Then they installed some barriers to make visibility worse (so drivers will not see the traffic on the main road until shortly before the stop sign, more or less forcing them to stop and take stock of the traffic situation, unless of course they are very irresponsible). Not sure if this has improved safety, but the barriers have been there for some years now, so I guess they were at least a bit successful...