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Interpretation Letter 4(09)-6 (I) - Freeway Entrance Ramp Control Signals

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DOT Logo Memorandum
U.S. Department
of Transportation
Federal Highway


Subject: MUTCD Official Interpretation 4(09)-6 (I)
Freeway Entrance Ramp Control Signals
Date: January 5, 2011
From: Mark Kehrli
Transportation Operations
In Reply Refer To: HOTO-1
To: Derrell E. Turner
Division Administrator (HAD-MN)
St. Paul, Minnesota
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Recently we received e-mails from Mr. William Stein of your office regarding Paragraph 4 of Section 4I.02 of the 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD). This inquiry is about a metered two-lane entrance ramp on which the two lanes are separately-controlled such that the green signal indications are not displayed simultaneously. Your office asked whether it is allowable for such a ramp to use only roadside post-mounted ramp control signal faces rather than overhead faces, if two faces (one high-mounted and one low-mounted) are provided for each lane.

In the January 2008 Notice of Proposed Amendments to the MUTCD, it was proposed that two faces be required for each lane of a multilane metered ramp with non-simultaneous operation of the lanes. That proposal did not include any requirement for the signal faces to be mounted overhead. Comments to the docket included concerns about challenges of mounting two faces for an interior lane when there are three or more ramp lanes operated non-simultaneously. After reviewing all docket comments, the FHWA decided to adopt language for Paragraph 4 of Section 4I.02 in the December 2009 Final Rule to require one signal face over each separately-controlled ramp lane when there are two or more such lanes, plus a Guidance statement (Paragraph 5) recommending consideration of additional side-mounted faces.

In reviewing our process for coming to this decision, we now recognize that we were in error to apply the requirement of Paragraph 4 and the recommendation of Paragraph 5 to ramps having only two separately-controlled lanes. It was intended that such requirement only apply to ramps with three or more separately-controlled lanes, thereby addressing the docket comments about challenges of mounting two faces for interior lanes on ramps having three or more lanes. When there are only two separately-controlled lanes on a ramp, we believe that those lanes can be satisfactorily controlled with two side-mounted faces (one mounted at normal height and one mounted low on the same pole, as allowed by Paragraph 9) adjacent to each of the two lanes and that display meets what was intended by FHWA.

Therefore, it is our official interpretation of Section 4I.02 that:

Thank you for writing on this subject. We hope that our interpretation answers your question. For the next edition of the MUTCD, we will consider proposing revisions to the Section 4I.02 to more clearly and accurately reflect the intended application of provisions such as those you questioned. If you have any questions, please contact Mr. Wainwright by e-mail at or by telephone at 202 366 0857. Please note that we have assigned your request the following official interpretation number and title: "4(09)-6 (I) – Freeway Entrance Ramp Control Signals." Please refer to this number in any future correspondence regarding this issue.