Why Do Some Cars Have Red Turn Signals and Others Yellow?

When it comes to safety and effectiveness, there is a difference between the two colors

back of car, lights on road Photo: Getty Images

It’s common to see red turn signals in the U.S., even though many foreign countries use amber. In terms of safety and effectiveness, is there a difference when it comes to the color of your turn signals?

“There are different laws in different countries. In the United States, they still allow red turn signals,” says Mike Quincy, autos editor at Consumer Reports. “Yellow, or amber, makes more sense, because there’s a sharper contrast between the red brake lights and yellow turn signals.”

The advantage of amber rear turn signals is shown to be statistically significant. A study by the National Highway Traffic Safety Administration determined that amber signals show a 5.3 percent effectiveness in reducing two-vehicle crashes where a lead vehicle is rear struck in the act of turning left, turning right, merging into traffic, changing lanes, or entering/leaving a parking space.

So why does the U.S. even allow red turn signals? It could have to do with design aesthetics and the potential that it’s simply cheaper to use red for all rear lamps. And changes to standards require a rigorous scrutiny of cost vs. benefit.