> He argued (or the article did, can't seem to recall whom) that people had a specific level of risk they were prepared to accept: make it safer than that, and

> He argued (or the article did, can't seem to recall whom) that people had a specific level of risk they were prepared to accept: make it safer than that, and people drove less safely. Tom Vanderbilt also writes about this in his book "Traffic". I recommend it to anyone interested in the psychology of driving and road design.