Traffic engineers are rather obscure characters, though their work influences our lives every day. A geographic survey of East Lansing, Michigan, for example, once found that more than 50 percent of the retail district was dedicated to “automobile space”—parking, roads, and the like. By and large, the design and management of this space is handed over to traffic engineers, and our behavior in it is heavily influenced by their ­decisions.

In the last few years, however, one traffic engineer did achieve a measure of global celebrity, known, if not exactly by name, then by his ideas. His name was Hans Monderman. The idea that made Monderman, who died of cancer in January at the age of 62, most famous is that traditional traffic safety ­infra­structure—­warning signs, traffic lights, metal railings, curbs, painted lines, speed bumps, and so ­on—­is not only often unnecessary, but can endanger those it is meant to protect.