Hi-viz clothing and safety

cycle-outfits-ian-walker-researchThe drumbeat to encourage bicyclists to always wear “hi-viz” (hi-vis, high-visibility, fluorescent) colored clothing — even in daylight — seems to become louder and louder. But it appears there is scant evidence suggesting any measurable safety improvement. The best I get when asking what evidence exists is something along the lines of “it can’t hurt”. (this has echos of the never-ending helmet wars; helmet’s claimed safety improvements have been overstated, sometimes vastly, over the years)

There is a dark side (pun intended)  to this fallacy, which is that once everyone believes it, it will become required — even if there’s no provable benefit — which will both discourage and reduce the amount of cycling, and will place additional legal burdens on bicyclists involved in crashes; it will become another Cheney, a landmark helmet personal injury case. I.e. everything that happens to a non-hi-viz wearing cyclist then becomes their fault, because as the story goes, the motorist that ran over the cyclist did so only because the cyclist failed to wear hi-viz. And any injuries/losses that occur then can’t be recovered.

In daylight, bicyclists make themselves safe by riding in a manner which makes them relevant and visible to other traffic: ride in a predictable manner, and follow the rules of the road, including controlling the lane when narrow.

Difficult lighting conditions, when the sun is at a very low angle, indicate a need for active lighting. And nighttime riding indicates a definite requirement for a headlight, and a red rear reflector (and/or taillight). Reflective clothing at nighttime is probably beneficial (research?) and note that hi-viz and reflective are not the same thing, although many hi-viz garment combine elements of both.

Some references

High vis clothing doesn’t make cars pass you more safely, says new study The article in road.cc refers to a  2013 study published by our old friend prof Ian Walker. Earlier very novel research by Walker had him donning a long blonde wig to show that motorists pass unhelmeted, female-appearing bicyclists with wider margins. “The researchers conclude that there is little a rider can do, by altering their outfit or donning a high-visibility jacket, to prevent the most dangerous overtakes from happening”.  Full study is:

The influence of a bicycle commuter’s appearance on drivers’ overtaking proximities: an on-road test of bicyclist stereotypes, high-visibility clothing and safety aids in the United Kingdom

A review published in AA&P, Exposure measurement in bicycle safety analysis: A review of the literature couldn’t find any evidence of benefit…  “Wearing visible clothing or a helmet, or having more cycling experience did not reduce the risk of being involved in (a crash)”.

A Cochrane Colaboration literature review: Interventions for increasing pedestrian and cyclist visibility for the prevention of death and injuries found “Fluorescent materials … improve detection and recognition in the daytime” but “the effect of visibility aids on pedestrian and cyclist safety remains unknown”.

For now, this is SATIRE
For now, this is SATIRE

AsEasyAsRidingABbike.wordpress.com point out… and this satirical article with a great picture, but how long before satire becomes reality???

This 2016 article from Austrailian TheAge Bike safety: the great fluoro fallacy offers some more cognition references, and refers to the classic gorilla-basketball research/”inattention blindness“, research that implies conspicuity and cognitive recognition are two separate things. It also references research that I many not be able to find from Dr Sandar Tin Tin‘s PhD research.

The page at cyclingfallacies.com has a nice round-up of links.

Hi-viz Clothing Laws

The last People For Bikes legislative review webinar (Jan 2016) showed there were six (!) bills submitted around the country in the previous year’s legislative season mandating the use of various variations of reflective and/or hi-viz clothing; several would have required their use 24 hours a day (would have required use of reflective clothing in the daylight). All of the bills died. Curiously, the PfB’s legislation person Alex Logemann flat-out stated they had no idea where these bills were originating. My best guess is these bills are being introduced by random well-meaning but misinformed lawmakers.

Here, for example is South Dakota’s HB1214:

Any person operating a bicycle on a highway shall wear garments made of fluorescent or reflective material. A violation of this section is a Class 2 misdemeanor

(note that in engineering and legal parlance, a ‘highway’ is any street)





Leave a Reply

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