What’s wrong with sharing? What’s wrong with courtesy?

image: www.bikede.org
image: www.bikede.org

Bicyclist advocates have been pointing out for years that the “Share the Road” message is problematical for bicyclists — that nobody really understands what it’s supposed to mean — the meaning is, at best, unclear and therefore readily mis-interpreted.

As of August 2015, there’s been a perceptual study published that gives statistically validated heft to the argument: in short, the study compared people’s perceptions of four treatments on two roadway configurations, the four were:

  • no sign
  • Share the Road
  • Bicycles may use full lane (BMUFL)
  • Shared Lane Marking (a.k.a. “Sharrow”)

Results were clear: BMUFL “wins”. The only thing positive that can be said for StR is that it was no worse than no treatment at all.

The full study is free and online here, I would encourage everyone to read it, it is clear and concise in explaining the situation, and is only a few pages long:

“Bicycles May Use Full Lane” Signage Communicates U.S. Roadway Rules and Increases Perception of Safety George Hess, M. Nils Peterson

If you are too lazy to read the study here is the study’s conclusion, my emphasis added:

Of the three bicycle-related traffic control devices we tested, “Bicycles May Use Full Lane” signage delivered the message about the rights and responsibilities of bicyclists and motorists with respect to travel lane occupancy most consistently: bicyclists are permitted in the travel lane and need not move to allow motorists to pass them within the lane. Although Shared Lane Markings did increase comprehension in some cases, they did not deliver the message as consistently as “Bicycles May Use Full Lane” signage. We speculate that a combination of “Bicycles May Use Full Lane” signage and Shared Lane Markings might be particularly comprehensible. “Share the Road” signage failed to provide any additional comprehension in this regard when compared to the unsigned roadways in any of our tests. “Bicycles May Use Full Lane” showed particularly strong increases in comprehension for novice bicyclists and private motor vehicle commuters, critical target audiences for these traffic control devices and for efforts to promote bicycling in the US.

Now if we could just get cities, counties and the state to not use lanes that seem to be wide, but aren’t (anything wider than about 10′ but narrower than about 15′); or worse yet: fake bike lanes. It should be noted that the study specifically avoided these cases by presenting an illustration showing clearly narrow lanes, and no shoulder or bike lane.

Here’s the MUTCD technical description of BMUFL and Shared Lane Markings.

FHWA (#fhwa)

This non-standard “Share The Road” signs as seen in City of Phoenix, Tempe and elsewhere; photo richardcmoeur.com

The FHWA (the folks that bring us the MUTCD) has a nice explanation of why the share the road plaque shouldn’t be used, the same reasoning extends to non-standard share the road, from the part 9 MUTCD faq:




Q: Should “share the road” signing be used to inform drivers of the likely presence of bicyclists and to inform them to pass bicyclists safely?

W11-1 with W16-1. Allowed but not “best practice” according to the FHWA.

A: The SHARE THE ROAD (W16-1P) plaque was introduced into the MUTCD in the context of slow-moving farm equipment with no associated mention of bicyclists. Since that time it has become prevalent in conjunction with the Bicycle (W11-1) warning sign with the intent of warning drivers of the presence of bicyclists and warning drivers to pass safely. Research has shown that the “share the road” message when applied to bicyclists does not adequately communicate the responsibilities of either user group on the roadway. Road users are unclear whether “share the road” means that drivers should give space when passing or that bicyclists should pull to the side to allow drivers to pass. Where bicyclists are expected or preferred to use the full lane, that message is more clearly communicated with the Bicycles May Use Full Lane (R4-11) sign, supplemented by shared-lane markings as appropriate. When using the Bicycle (W11-1) warning sign, many jurisdictions have phased out the use of “share the road” in favor of an IN LANE or ON ROADWAY word message plaque, more clearly indicating the condition ahead instead of giving an unclear instruction. It is still compliant with the MUTCD if a jurisdiction chooses to post a SHARE THE ROAD (W16-1P) plaque under a Bicycle (W11-1) warning sign, but it would not be the best practice.


The Bicycle Technical Committee (BTC), of the National Committee on Uniform Traffic Control Devices (NCUTCD) is tracking this issue in their current (as of 10/2017) BTC Priorities list:

ON ROAD Plaque (Replacing “Share The Road”) / PENDING. Numerous reported concerns and misinterpretations of “Share The Road” plaques. Some jurisdictions (Delaware, others) have discontinued W16-1P use. Intent is to “retire” W16-1P and replace with new “ON ROAD” plaque for same application. Use “ON ROAD” in lieu of “IN LANE” or “ON SHOULDER” for greater scope of application and to not send unintended messages. Draft proposal from Schultheiss April 2016. Rejected by RWSTC June 2016 on basis that proposed legend has not been evaluated. Research problem statement pending. TCD Pooled Fund Study did NOT approve for testing FY 2017.

Comments on “Share The Road” signs

A series of comments I cut and pasted on the topic–

  • The use of a W11 series warning sign with the Share The Road plaque was made to allow the plaque to be used with a variety of existing mode-specific signs. However, this creates the impression that the act of occupying the roadway in that mode of travel is inherently dangerous. Bicyclists share public roadways every day with other traffic, and three decades of crash data have clearly shown that overtaking/sideswipe crashes are rare and that most bicycle-motor vehicle crashes happen at intersections (which this sign won’t help).
  • To my knowledge, there are no hard data or good studies that show that “share the road” signs of any type or design induce any sort of meaningful positive changes in road user behavior. A survey in Colorado showed that respondents liked the sign, but the study sample wasn’t balanced (80% bicyclists). Advocates and many members of the public seem to have a belief that the existence of a “share the road” sign automatically ensures that people will read the sign, interpret the sign in the same way they do, and then modify their behavior in the desired manner. There is already a possibility that these signs may be ineffective. What is worse is that the presence of these signs could create an incorrect belief that the “sharing” problem has been fixed, when in reality there is no change in behavior or safety.
  • There seems to be no universal definition of “sharing” that is understood by all road users in all situations. On a roadway where the rightmost travel lane is wide enough for a motor vehicle and bicyclist to travel side by side, the concept of “sharing” seems simple and intuitive. However, in locations where the rightmost travel lane is too narrow for a bicyclist and motorist to safely travel side by side, ARS 28-815.A.4 releases bicyclists from the “as far right as practicable” restriction. This can lead to misunderstandings (and harassment) where motorists believe the bicyclists aren’t “sharing” when operating in this manner – even though the cyclist is operating in a way that ensures their greatest overall safety, and eliminates the ambiguity of whether a motorist can “squeeze by” in the same lane (which can indeed truly endanger a cyclist).
  • If the location in question has a rightmost travel lane width less than 14 ft and a shoulder width usable by bicyclists of less than 4 ft, than a R4-11 Bicycles May Use Full Lane sign may be more appropriate, with concurrence from the Regional Traffic Engineer.

What’s wrong with courtesy?

Well, like sharing, nothing… except it is often mis-represented and mis-interpreted. Courtesy, or the c-word as I now like to call it, is a dead end for bicyclist-safety and use of the term should be abandoned entirely with regard to urban bicycling. The subject is appropriate when discussing “control and release” which is typical of rural roads. The impeding 5-or-more statute (28-704C) is in a sense forced courtesy on typical rural road, and rarely if ever applies on urban roads.

There was an op-ed type column (out of Maine, i think) My voice: City’s policy changes make bike riding safer written by LCI Michael Christensen. It did a great job of spotlighting the manner of collisions that befall most bicyclists in his town :

Riders are not dying because they are trying to share space (with same-direction traffic). They are dying because they are being wrongly advised that sidewalk riding is safer. Riders who ride in the roadway courteously and according to traffic laws are far more visible, predictable and communicative. Therefore, they are far less likely to be injured or killed by anybody’s drunkenness or unwillingness to actually look where they’re going.

I would complain about the “courteously and”, that it should have just been left out of the sentence. And I would even argue that it is motorists demanding, or bicyclists feeling the need to supply, courtesy by riding at the edge that makes bicyclists less visible, less predictable, and less communicative — i.e. less safe.

3 thoughts on “What’s wrong with sharing? What’s wrong with courtesy?”

  1. Circa Jan 2015 communication regarding SR 88 (street view) …ADOT has installed very few W16-1 SHARE THE ROAD plaques under a W11-1 Bicycle warning sign in other Districts, most recently along SR 179; however, part of our reluctance to install this sign assembly is based on reports that it, “does not convey a clear message, as different users have different understandings of what sharing of the road means”(http://www.ncutcdbtc.org/sponsors/fall05/bike01-bmufl.pdf). You may have heard: “Delaware Department of Transportation announced that, effective immediately, Delaware would stop using the MUTCD-approved ‘Share The Road’ plaque (W16-1P). More, the department would also start removing all ‘Share The Road’ signs currently installed in Delaware” with backing of that State’s bicycle advocacy org (see http://www.bikede.org/2014/04/07/why-share-the-road-is-gone/; for another earlier advocate’s report, see http://www.humantransport.org/bicycledriving/library/Share_Road.pdf). I think education of all road users is the key with, perhaps, use of Bicycles May Use Full Lane sign http://wwwa.azdot.gov/traffic/moas/pdf/r/r04-011.pdf and/or Shared Lane Markings (http://mutcd.fhwa.dot.gov/htm/2009/part9/part9c.htm#section9C07).

  2. Wonderful video of a traffic stop. The exchange was very civil. A little bit long, but the part about BMUFL signs was very interesting, direct link to 3:30 —
    Bicyclist: …and what the sign (along this road where he was pulled over) says is ‘Bicyclists may use full lane’
    Officer: the whole lane? (sounding rather incredulous)
    [some description of the MUTCD and CAMUTCD follows], then, interjecting
    Officer: I’ve been an officer for ten years, and I know bicycles can’t ride down the middle of the road
    [officers and other often hyperbolically refer to cyclists riding in the middle of a narrow lane as the ‘middle of the road’]

    CA law is identical to AZ (and nearly all other states except a few that have no ‘as far right as practicable’ provision) in this regard — Bicyclists riding in a lane which is too narrow to share may (legally), and should (for safety), ride near the middle of that lane. Bicycles May Use Full Lane — just like the sign says, and whether or not there’s a sign there.
    In Arizona this is 28-815A exception #4.

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