Bicycle Passing Law Sign

r4-11 with Change Lanes To Pass placard

Despite availability of BMUFL/Change lanes to pass signs; there has been work ongoing to approve a whole new sign which would specifically refer to state passing law requirements in states with so-called numerical passing laws. According to NCSL as of April 2020, 34 states have such laws, almost all of them specifying a minimum of 3 feet, and most have some loopholes.

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).

The conclusion / recommendation was for Alt. 3. as being the “winner”. Notably, a major knock against signs, such as the one being used in Phoenix since 2007, using an arrow (Alt 4, 5, and 6) was that a significant fraction of people believed they indicated the bicyclist must provide the clearance, and not the other way around; and seems to be a good reason to get rid of the old-style Phoenix signs ASAP.

BTC / NCUTCD proposed Bicycle Passing Law sign

The sign depicted at right, shown with optional STATE LAW header, was passed at the June 2018 National Committee on Uniform Traffic Control Devices (NCUTCD) BTC meeting; Similar to Alt 3. except it moved the relative position of the logo, and substituted MUST for SHALL. Here is the full document as approved by the BTC 6/20/2018; and by the NCUTCD council 1/11/2019.

It contains some background on the modifications, compared to the PFS sign, and how that happened.

Section 9C.06a Bicycle Passing Clearance Sign (R4-xx)
Where the law requires a motorist overtaking a bicycle to pass with some specified clearance, the Bicycle Passing Clearance (R4-xx) sign may be used along roadways where bicyclists operate to remind motorists of the required (minimum) passing clearance.
The legend STATE LAW may be added within a header panel above the Bicycle Passing Clearance (R4-xx) sign in accordance with Section 2A.15 based on engineering judgment.
The Bicycle Passing Clearance (R4-xx) sign shall indicate the passing clearance distance required by law.
The Bicycle Passing Clearance (R4-xx) sign should not be used on roadways with separated bicycle lanes.

There is no reference to BMUFL and no guidance whatsoever on when one might choose one versus the other, as it stands, it’s left totally to the predilections of whoever is putting up the signs.

Be that as it may, I consider the BMUFL/CLtP sign to be a 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.

The 3-foot law was passed in Arizona twenty years ago in 2000. I don’t believe it has lived up to its hype, here or elsewhere. Drivers who make close (or worse) passes tend to fall into three distinct categories:

    1. intentional, this is a criminal matter. Often involves driver shouting, blaring horns, revving engine, surging ahead then slowing down.
    2. misjudged distance; and tends to happen when a bicyclist rides at the right edge of a narrow lane.
    3. oblivious due to distraction. These are by far the most dangerous. Virtually all “drifing“, and most “strike-from-behind” type crashes are this type; and has nothing to do with making a prudent passing distance decision.

The latter two being unintentional. Police virtually never issue citations except in the event of a crash.

Phoenix 2019?

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.

The PASS MIN 3 FT (i.e. “Alt 1.”) version of the sign has already been installed by City of Phoenix, as of late 2019 see e.g. this facebook post.

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

I don’t know the decision process about why that version of the design was chosen — in any event one that was used  is highly  unlikely to be the final, approved design for this message.

As mentioned above, I think a more appropriate sign where the lanes are too narrow to share, is to use a BMUFL with/Change lanes to pass.






Share the Road?

On the related topic of signs, see whats-wrong-with-sharing to understand why the “share the road” message is problematic, and is in the slow process of being abandoned. If nothing else, a standard bicycle passing law sign would probably help hasten their demise.


Here is some background (old?) information gathered from many states, with some helpful details from Richard Moeur given for ADOT.


3 thoughts on “Bicycle Passing Law Sign”

  1. As a former bicycling safety instructor, I’ve never been enthused by minimum passing laws because (1) they are almost never enforced (as noted above), (2) (related) they are unenforceable, (3) There are already applicable laws on the books which cover safe passing of vehicles and (4) it would be much better to teach everyone that cyclists should assertively provide for their safety by riding near the middle of the lane rather than slinking along the curb — or in a bike lane.

    #4 above would require an extensive education campaign to teach everyone, especially including motorists and police.

    Where faster traffic is impeded, cyclists should find a safe place and then temporarily move over to facilitate passing. This is called “control and release” — one controls the lane where passing is not safe and then releases and traffic behind when it can be done safely.

    This assertive cycling actually helps motorists avoid mistakes.

    As for the BMUFL sign, I’d much rather the word “may” be removed and then color the sign yellow, which makes it advisory (much like the yellow signs advising the speed for curves in the road).

  2. I believe the BMUFL/Change lanes to pass sign is the appropriate message to convey to motorist. Many people do not understand that a 12 foot lane is too narrow to share. Ref: If I ride in the right tire lane, motorist get lazy and make a lane split. This usually results in less then 3 feet of passing clearance. In our culture most people believe bicyclist should ride on the edge line. This is where very scary close calls and sideswipes occur.

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