These were of the "spanwire" type construction, commonplace from the 1880s (days of the earliest arc lights) through the 1960s.

Modern mercury vapor light sources with brighter illumination slowly but surely replaced older installations like this via long mast arms.

However suspension-type street lighting like this such still exists, scattered across the US with numerous installations in southern CA, Milwaukee, WI, Detroit, MI and other communities who still prefer this type of intersection street lighting, albeit mostly converted to modern, more efficient light sources.