The Monday Morning Commute: Ask Traffic Engineer Paul Basha: When A Driver Enters An Intersection On A Yellow Light, Are They Legally Required To Clear The Intersection Before The Light Turns Red?

By Paul Basha, traffic engineer, Summit Land Management

When a driver enters an intersection on a yellow light, are they legally required to clear the intersection before the light turns red?

Yes or no – depends on the state.

Yellow lights first appeared in 1920, invented by a police officer, when the first three-color traffic signal in the world was installed in Detroit, Michigan. For a century, when drivers everywhere see a yellow light, they must worry about stopping and being rear-ended or going and being hit from the side. And now there’s that $165 ticket possibility.

(Much of the information in the following four paragraphs is from a January 2018 Institute of Transportation Engineering Journal article, authored by three individuals including Northern Arizona University Associate Professor of Civil Engineering Edward Smaglik.)

In Rhode Island, West Virginia, Louisiana, and Tennessee; drivers cannot be in the intersection when the red light appears. In 37 states, if a driver enters the intersection on a yellow light, they have the legal right to continue through the intersection after the red light appears.

In Oregon, Nebraska, Iowa, Wisconsin, Michigan, Mississippi, Virginia, New Jersey, and Connecticut; the law is nuanced. In these states, drivers should stop when the yellow light appears, unless it is not safe to stop. Much judgment by you and the observing officer or camera.

The states of Arizona, Nevada, Nebraska, Oklahoma, Michigan, Tennessee, Virginia, Kentucky, and New Hampshire state in their driver training manuals that drivers are prohibited from accelerating to enter the intersection while the light is yellow.

The Arizona Driving Manual states:

“Th[e yellow] signal means CAUTION. A steady yellow light is a warning that the light is about to turn red. If you have not entered the intersection, you should come to a safe stop. If you are already in the intersection, you should continue moving and clear it safely. Speeding up to “beat the light” is illegal and could cause a crash.”

The Arizona Driving Manual also states:

“Th[e green] signal means GO. . . . Yield to any vehicle that is already in the intersection when the light changed.”

Arizona Revised Statutes 26-645 states:

“1. Green indication:

(a) Vehicular traffic facing a green signal may proceed . . . . Vehicular traffic, including vehicles turning right or left, shall yield the right-of-way to other vehicles and to pedestrians lawfully within the intersection or an adjacent crosswalk at the time the signal is exhibited.” [Emphasis added.]

In Arizona, when we enter an intersection on a yellow light and the light turns red, we’re happy knowing we will not be ticketed. However, if we’re stopped at a red light, and the light turns green, we are unhappy if a car on the other street is still in the intersection. In fact, if we leave quickly and hit that car; the collision would be our fault as we would have violated ARS 26-645.

The definition of an intersection is vital for a running red light citation – by human or camera. Also helpful to police officers assigning fault for a collision. The intersection begins at the curb line – shown on the pavement as the brown-red line. Notice it is also on the lane line between the right-turn lane and the through lane.

Intersections with red-light photo enforcement cameras often have these lines. They look good in the portrait of you in your car.

These red-brown lines are visible at the Scottsdale intersection of Greenway-Hayden Loop Road and Frank Lloyd Wright Boulevard – if you keep your eyes on the road. Though watching traffic, signs, and signals is preferred.

Don’t tell anyone that these lines are only used where there is a red-light camera. Part of the value of red-light cameras is that drivers think they might be anywhere.

Curious about something traffic? Call or e-mail Paul at (480) 505-3931 and


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