This image shows the Mackinac Bridge illuminated along the roadway and cabling in a night setting. The streaks of light below are an effect of the lights reflecting off the water of Lake Michigan during a long exposure.
The description states:
THE MACKINAC BRIDGE
State of Michigan
Gaily lighted during the hours of darkness. The roadway lights are a sparkling blue-green color, the bale lights a deep amber, the navigation lights on top of towers are red and flash constantly. Two green lights mark the midpoint of the center span, and two red lights near the towers of the center span mark the channel for the lake boat traffic. On evenings when the water is calm, beautiful reflections are the joy of camera enthusiasts. This multi-million dollar bridge, dedicated in June of 1958, spans the Straits of Mackinac, joining the lower and upper peninsulas of Michigan.
–This card dates from the 1950s.