Tom Vanderbilt in Slate Magazine writes about The quest to design a better stop sign.

[T]rying to improve driver behavior through better signage is as futile as fighting illiteracy with better fonts.

Engineers really need to learn about risk compensation.
Not all safety improvements are futile, but there is a response, so drivers who are protected use some of the safety improvement to behave in a riskier way, as in the video below. This does not imply they necessarily die.