Three Second Yellow Light Signal Requirement

Attorney General
Thomas C. Horne
Date Posted
Opinion Number
I11-005 (R11-008)
Three Second Yellow Light Signal Requirement
I11-005.pdf100.31 KB


The Honorable Frank Antenori
Arizona State Senate

Question Presented

Does Arizona Revised Statutes (“A.R.S.”) § 28-643, which requires a minimum yellow light duration of three seconds, apply to yellow lights for left turns?

Summary Answer

Under A.R.S. § 28-643, all traffic control devices must conform to the specification that the yellow light duration be at least three seconds. A plain reading of the statute indicates that the statute’s language applies to all traffic lights, including those for left turns, and the legislative history confirms this interpretation.


Arizona Revised Statutes § 28-641 provides that the Director of the Department of Transportation “shall adopt a manual and specifications for a uniform system of traffic control devices for use on highways in this state.” In the 2010 Regular Session, the Arizona Legislature enacted and the Governor signed House Bill 2338, amending A.R.S. § 28-643. See 2010 Ariz. Sess. Laws ch. 213, § 1. The measure provides as follows:

Local authorities in their respective jurisdictions shall place and maintain the traffic control devices on highways under their jurisdiction as they deem necessary to indicate and to carry out this chapter or local traffic ordinances or to regulate, warn or guide traffic. All traffic control devices erected shall conform to the manual and specifications prescribed in § 28-641. The manual shall include the specification that the yellow light duration must be at least three seconds.

According to your letter, some municipalities have determined that the statute’s last sentence does not apply to yellow light durations for left turns and have allowed the default timers on yellow lights installed by private contractors to run for periods of time less than three seconds on left turns.


I. The Plain Meaning of “Yellow Light Duration” in A.R.S. § 28-643 Includes the Duration of Both Yellow Lights for Straight-ahead Driving and Yellow Lights for Left Turns.

If a statute’s language is plain and unambiguous, courts interpret the language as written without resorting to other methods of statutory interpretation. Mid Kansas Sav. & Loan Ass’n v. Dynamic Dev. Corp., 167 Ariz. 122, 128, 804 P.2d 1310, 1316 (1991).  In this case, the statute does not distinguish between traffic lights for straight-ahead driving and those for left turns. If the Legislature intended the term “yellow light duration” to apply only to straight-ahead driving, it could have specifically exempted left turns. It did not do so and instead chose more general language applicable to both left turns and straight-ahead driving. The statute’s plain language encompasses the duration of yellow lights for left turns because these devices fall within the general term “yellow light duration.”

II. The Legislative History of A.R.S. § 28-643 Confirms that the Phrase “Yellow Light Duration” Applies to Left Turns.

The available legislative history for § 28-643 confirms that the legislature did not intend to distinguish between left turns and other yellow lights. See State v. Gomez, 212 Ariz. 55, 57, ¶ 11, 127 P.3d 873, 875 (2006) (noting that where a statute is ambiguous, the court may consider other tools of statutory construction). For example, legislative records demonstrate that in response to questions regarding the measure, the bill’s sponsor indicated that it was intended to apply to both left-hand turns and straight-ahead driving. See Minutes of H. Comm. on Transp. & Infrastructure, 2010 Leg., 2d Reg. Sess. at 3 (Jan. 28, 2010).


Under A.R.S. § 28-643, the requirement that the duration of a yellow light be at least three seconds applies to both left turns and straight-ahead driving. Consistent with the legislative history, a reading of the plain language “yellow light duration” compels the conclusion that the rule applies to all yellow lights.

Thomas C. Horne
Attorney General