Change Lanes to Pass

R4-11 BMUFL sign with Change Lanes to Pass placard

There’s a new sign in town, well it’s actually a plaque, the R4-11aP CHANGE LANES TO PASS (“CLtP”)was just recently added to Arizona’s Manual of Approved Signs (MOAS) in March of 2017.

R4-11aP Change Lanes to Pass placard

The sign is available to be added as a plaque in conjunction with the pre-existing R4-11 (Bicycles) MAY USE FULL LANE (“BMUFL”), which made it’s debut in the 2009 edition of the MUTCD, and was finally added to Arizona’s MOAS in June 2013.

Most lanes in Arizona, and elsewhere for that matter, are designed to accommodate only the width of one vehicle, not a

R4-11 Bicycles MAY USE FULL LANE

bicycle and a vehicle side-by-side safely. In this situation, bicyclists need not (legally) ride as far to the right as practicable, but rather are instructed to ride near the center of the lane as best safe practice, this position will make the bicyclist more visible to other motorists, giving them more time to avoid abrupt, unsafe movements.

Below is a typical laned arterial road configuration, this happens to be in Tempe… The lanes are too narrow to share safely side-by-side. Non-standard signs, such as the “Share the Road” should be replaced —

Elliot Road, eastbound east of Priest Drive, City of Tempe. Sign placed by the city reminds users to “Share the Road”. Posted speed limit 45mph. Even the fastest bicyclists will be traveling well below the posted speed limit. This arterial, like most, has lanes which are “too narrow to share safely side by side”, and as such, cyclists going straight ahead are advised to ride near the center of the right-most through lane. Motorists wishing to overtake must change lanes (at least partially) to pass legally and safely.

Sign Size

As noted in Table 9B-1. Bicycle Facility Sign and Plaque Minimum Sizes of the MUTCD the minimum size of this sign is 30″ wide.

Law Updates (#law)

Some states have begun to include statute updates requiring overtaking drivers (i.e. “drivers of motor vehicles”)  to change lanes to pass under certain conditions

  • DE Delaware – 2017 Bicycle Friendly Delaware Act
  • WA Washington – 2019 as part of an update to their vulnerable user law.
  • OK Oklahoma – 2019 HB2453; amending 47 O.S. 2011, Section 11-1208
  • IA Iowa — (?i think?) this was as result of a published court opinion(?) I don’t remember what i meant by this?

The League of American bicyclists has incorporated a CLtP provision into the model safe-passing law; though it is odd/weak/unnecessary language tacked onto the multi-lane road provision.


Good explanation of change lanes to pass messaging from suggests theses actions

  • Phase out “SHARE THE ROAD” plaques in favor of “CHANGE LANES TO PASS” plaques
  • Educate law enforcement about changes to the passing law and recommended technique for passing bicyclists
  • Produce motorist education/PSAs on safe passing practices
  • Update driver education curriculum
  • Change-lanes-to-pass law

More new signs? — Bicycle Passing Law

The material that used to be here was moved to its own article on June 2020.


This sign seems misguided, for reasons I will elaborate on later, but there’s almost certainly going to be a new official sign for use in states, AZ being one of them, that have numerical passing laws. There are any number of home-brewed (non-standard) such signs in use all over the place (e.g. City of Phoenix has been using this sign since 2007); hopefully this will at least clean up that mess.

For a sign to become “official” I’m referring to it ultimately being added to the MUTCD, and subsequently adopted for use within Arizona by being added to the Arizona’s MOAS. While the MUTCD is an official government document maintained by the FHWA; before that happens there’s this elaborate quasi-official national process of committees and sub-committees within the traffic engineering community involving the NCUTCD and the BTC. See here for some explanation of all those acroynms.

In any event, somehow someone got together some money to perform a human-factors study on different versions of signs; that resulted in the Traffic Control Devices Pooled Fund Study;  Comprehension and Legibility of Selected Symbol Signs Phase IV (sometimes referred to as the TCD PFS) which published results in December 2017. The meat of the study is they round up a bunch of motorists (and in our case, also bicyclists) and are shown differing versions and asked to answer questions regarding comprehension, legibility, etc, and based on responses develop a recommended sign. Here is the intro:

Bicycle Passing Law Over 20 states have passed legislation requiring motorists to provide a minimum of 3 feet of clearance when passing bicyclists on the roadway. Yet, there is not currently a standard sign that provides motorists with notice of this law. Many states and local highway agencies have developed their own signs to convey this message. These signs and alternatives to these were tested to ensure comprehension and legibility.

(as an aside, a Rail/Flangeway Gap Bicycle Warning sign was also in the same study).


STATE LAW / PASS [Bike-logo] 3FT MIN
(known as the “Alt 1” version)

With the “state law” heading against yellow background and optional. The number of feet changes to match the particular state’s law; which vary I think from 2 to 4 feet.

Something was passed at the June 2018 National Committee on Uniform Traffic Control Devices (NCUTCD), as described in this LAB post:

A standard layout for a sign indicating a minimum distance (typically 3 feet) for passing bicyclists was approved. The sign was selected upon completion of sign recognition and human factors testing to make sure that motorists and bicyclists properly understood the sign. Three-foot passing laws have been passed by at last 33 states in the last few years, and many states developed their own signs, all different. Agencies wishing to post this type of sign may wish to use the version that was approved by the committee. —

I’m confused because the approved change on NCUTCD’s site, lists this document. Which contains the wordier/busier message of:

(a slight modification to the “Alt 3” version)

This was approved by the BTC 6/20/2018; and by the NCUTCD council 1/11/2019. It has the the same STATE LAW optional header. Here is some background (old?) information gathered from many states, with some helpful details from Richard Moeur given for ADOT.

The PASS MIN 3 FT version of the sign has already been installed by City of Phoenix, as of late 2019 see e.g. this facebook post.

A lane change is required to pass bicyclists on roads such as these anyway.
A BMUFL sign would be more appropriate here in conveying expected behavior of both bicyclists and motorists. Installed by City of Phoenix in late 2019.

Be that as it may, I consider the BMUFL/CLtP sign to be superior message in any narrow-lane situation. I fear clamoring for 3 foot signs everywhere are likely to crowd out the use of BMUFL signs — as I don’t see or think anywhere is going to use both, I mean on any particular road section.

Here is a post dated 2/17/2019 showing a draft version of the sign Phoenix ultimately used; the one pictured at right.

7 thoughts on “Change Lanes to Pass”

  1. under 2003 MUTCD, when “Bicycles May Use Full Lane” sign was proposed, that “word legend signs of this type may be installed at any time by agencies in accordance with Section 2B.54 of the MUTCD – even if the specific sign isn’t yet in the MUTCD” and that language is referenced here: “The proposed (Bicycles May Use Full Lane) sign uses a standard symbol and word legend, and therefore is already acceptable for use under Section 2B.54 of the MUTCD. However, the Bicycle Technical Committee believes that there is sufficient demand and justification for creating a standard design and code for this sign message.”

    Fast forward to 2009 MUTCD:
    Section 9B.14 Other Regulatory Signs
    01 Other regulatory signs described in Chapter 2B may be installed on bicycle facilities as appropriate.—2009-edition.pdf?sfvrsn=6

  2. Parts of the Natchez-Trace parkway was (recently?) signed with BMUFL / CLtP signage. Bicyclists are required by federal rules (see two-abreastness) to ride single file; this is not a conflict, just pointless, the lane is too narrow to share so bicyclists (any number of bicyclists, including one) may legally, and should, control the lane, while motorists who wish to travel faster may change lanes to pass when safe.
    See this criminal driver hit-and-run caught on camera running down a bicyclist on the parkway.

  3. From: Richard Moeur
    Sent: Tuesday, March 07, 2017 3:15 PM
    To: WebUpdates
    Subject: Manual of Approved Signs – March 2017 Update

    I have one more update for the ADOT Manual of Approved Signs…

    Added Signs:

    · R4-11aP Change Lanes To Pass

    Richard C. Moeur, PE
    Traffic Standards Engineer
    1615 W. Jackson St., MD 061R
    Phoenix, AZ 85007
    602.712.6661 (office)

Leave a Reply

Your email address will not be published. Required fields are marked *