Federal Highway Administration
U.S. Department of Transportation
400 Seventh St., SW
Washington, DC 20590

May 30, 2003

Refer to: HOTO-1

Ms. Elizabeth Lloyd-Weis
Signal Operations Unit
Wisconsin Department of Transportation
Transportation District 2
P.O. Box 798
Waukesha, WI 53187-0798

Dear Ms. Lloyd-Weis:

Thank you for your recent email communications with Mr. Scott Wainwright of this office requesting an Official Interpretation regarding Section 4D.07 of the Manual on Uniform Traffic Control Devices (MUTCD.)

Specifically, you asked for clarification of Standard item C.1.b. on page 4D-13 of the Millennium Edition of the MUTCD. This item states that, for a protected-permissive mode of right turn signal operation, a separate signal face is not required for the right turn, but, if provided, it shall be considered an approach signal face. It also states that, during the protected right-turn movement, the signal face shall simultaneously display a right-turn green arrow signal indication and a circular indication that is the same color as the signal indication for the adjacent through lane on the same approach as the protected right turn. You enclosed a diagram of an intersection and indicated that the right-turn movement in question was the northbound (NB) right turn from a side road onto a State highway. You asked:

When is a through lane considered "adjacent"? Is it dependent on the presence of an island between through lanes and the right-turn lane? Is it dependent on the size of that island? Does the type of island (i.e., raised, corrugated, etc.) have any impact?

The key to answering your question depends on what indication you intend to show to the NB right-turn movement when the NB/SB through phase is on. The NB right turn could have a green arrow during that phase if there is no conflict between the NB right turn and the SB left turn, or with a concurrent pedestrian phase. Assuming there is not a concurrent pedestrian phase, there would not be a vehicular conflict if the SB left turn is prohibited or moves only on a protected left-turn phase, or if the physical and painted channelization are such that the NB right and SB left each have their own dedicated lane on the eastbound (EB) departure roadway. This is because Section 4D.09 states that a steady green arrow or yellow arrow signal indication shall not be displayed to vehicular movements that are in conflict with other vehicles moving on a green or yellow signal indication, or in conflict with pedestrians crossing on a WALK or flashing DON’T WALK indication. Section 4D.09 also states that vehicles departing in the same direction shall not be considered in conflict if, for each turn lane with moving traffic, there is a separate departing lane, and pavement markings or raised channelization clearly indicate which departure lane to use.

If this is the case and you intend to display a green arrow to the NB right-turn movement during the NB/SB through phase, then what you would have is a "protected only" mode of right-turn operation, because the right turn moves only on a protected green arrow. So, you would provide a display in accordance with item B ("protected only mode") of the Standard in Section 4D.07, and the NB right-turn signals would be all arrows or circular red with yellow arrow and green arrow (B.1 or B.2).

On the other hand, if the NB right and SB left conflict with each other, or if there is a concurrent pedestrian phase, then you cannot display a green arrow during the combined NB/SB thru phase, so you must show the NB right turn a circular green. This would then be considered "protected-permissive mode" and would have to meet the requirements of item C of the Standard of Section 4D.07. The presence of a porkchop-shaped island of any size or type (raised or painted), as shown on your drawing, would not negate the requirement stated in C.1.b., and all signal faces for the NB approach would be considered "approach signals." As such, you would be showing a circular green simultaneously to the NB right turn and NB thru movements, and when NB through traffic has a circular red, the NB right-turn signal faces would also display a circular red. So, during the protected overlap phase, all signal faces for the approach would show circular red but the two faces for the channelized right-turn lane would also show green arrow.

If you have any questions, please call Mr. Scott Wainwright at 202?366?0857. Please note that we have assigned your request the following official interpretation number and title: "4-262 (I)—Wisconsin Section 4D.07." Please refer to this number in any future correspondence.

Sincerely yours,

/s/ Paul Pisano (for)

Shelley J. Row, P.E.
Director, Office of Transportation Operations