Which location is cited as the earliest reference found for pedestrian signals displaying the alternating dual words 'Wait' and 'Walk'?

Answer

New York City

In December 1938, signals reading alternately 'Wait' and 'Walk' were planned for Times Square in New York City, cited as the earliest reference for that specific dual-word indication.

Which location is cited as the earliest reference found for pedestrian signals displaying the alternating dual words 'Wait' and 'Walk'?
inventionSafetySignaltrafficcrosswalk