This seems really similar to techniques I've heard about in road design. A lot of safety improvements are pretty well compensated by changes in people's behavior. For example, if you make shoulders and lanes wider, people will feel like they're going slower and speed up to compensate. Even with things you wouldn't expect, like the dedicated/third brake light made mandatory for cars in 1986, there were significant changes in behavior (decreased following time) to compensate. However, there are many safety improvements that are more or less invisible to the end user. The best example is rumble strips -- they're never noticed until they do their job.