What to Do
Ease off speed, check the signal colour and allow for a queue beyond your current view.
A Detail to Remember
The miniature red, amber and green signal face is a warning that lights are ahead, not a signal telling you to go.
An Early Three-Colour Signal
Michigan’s handbook records a four-way red, yellow and green signal at Woodward Avenue and Fort Street in Detroit in 1920. The miniature signal face on this warning sign uses that familiar colour sequence.
Michigan Secretary of State: Signs, Pavement Markings and Signals ↗Understanding Warning Signs
Yellow warning signs ask you to anticipate a condition ahead. Read any distance or speed plaque with the main symbol, then adjust to what you can actually see on the road.
Sources and Review
Checked November 12, 2026. Explanations follow the sources below; image-specific observations refer to the pictured G1 Prep artwork.
Sign artwork: G1 Prep by Roadity. See our editorial policy.
