“Normal” pedestrian signals, ones where pedestrians “go with the flow” of motorized traffic, are older—but not as many decades older as I would have thought.

We haven’t determined exactly when or where the first pedestrian signals were installed, but it was apparently in the late 1930s.

The first “scramble” signals were apparently installed in the 1940s, with an extensive group installed in Denver circa 1950. Traffic engineer Henry A. Barnes, whose name became part of the nickname “Barnes Dance” for such scramble signals, brought the concept to Manhattan in 1962. The Wikipedia entry includes a list of such installations around the world, as well as links to references on the topic.

Exclusive pedestrian intervals remained rare until the 1990s, when traffic engineers began to pay much more attention to pedestrians, and the field’s literature began to again feature the concept. Cities that had removed such installations in the 1960s and 1970s began to look again at potential locations.

Some recent research indicates reduced numbers of crashes involving pedestrians at intersections with Barnes Dances, but in most urban situations this must be weighed against the delays it introduces to both motorists and pedestrians. In a common “go with the flow” intersection, the majority of pedestrians feel they are making progress, either toward their destinations or crossing one leg or the other of the intersection, at all times. A Barnes Dance requires them to wait longer to have more freedom of movement, which may not be effective (and thus may increase crashes) in places that don’t have a strong culture of “rule-following” among pedestrians.