Science Of Being Seen LIVE ONLINE TONIGHT

[The Spin Doctor]

Did you know the use of colour for conspicuity aids dates back centuries before the invention of hi-vis clothing? It's known that the Romans made extensive use of colour in their military formations!

Find out more about the use of colour in the Science Of Being Seen - live tonight at 8pm. Can't make it live? Watch it on catch-up!

https://ko-fi.com/s/1c5766dfaf

[Hot_Air]

Did you know the use of colour for conspicuity aids dates back centuries before the invention of hi-vis clothing?

Indeed. Here’s an example from an early Rukka Roman catalog.

[Horse]

'Course it's roamin. Not on a lead.

[The Spin Doctor]

I may have mentioned I came across chickens with hi-vis vests on

[Mr. Dazzle]

People wore different coloured stuff in the past, for various reasons!?

I thought it was all in black and white.

[Scootabout]

I may have mentioned I came across chickens with hi-vis vests on

For crossing the road?

[Hot_Air]

Find out more about the use of colour in the Science Of Being Seen

Imitation is the best form of flattery:
The science of being seen: a guide to safer riding

[The Spin Doctor]

I found that a few weeks ago - a credit for the name check would have been nice

[Hot_Air]

@The Spin Doctor You’ve highlighted the ineffectiveness of hi-viz vests and suggested sleeved hi-viz jackets would work better during daytime. Unusually, for road safety research, a randomised controlled trial (RCT) has been done on sleeved fluo yellow jackets in daylight, and the findings for cyclists agree with your hypothesis.

It’s unusual because it’s an RCT, whereas observational studies are far more common in road safety research. An observational study can only tell us about an association (e.g. people with ginger hair are associated with fewer motorcycle accidents), not causality (ginger hair reduces accident risk). We need RCTs to investigate causality. And RCTs are less influenced by confounding factors.

Highlights
• A randomised controlled trial with 6793 cyclists shows a reduced accident risk due to a yellow bicycle jacket.
• The test group had 47% fewer multiparty accidents with personal injury.
• The test group had 55% fewer multiparty accidents against motorised vehicles.

Abstract

This study is the first randomised controlled trial (RCT) of the safety effect of high-visibility bicycle clothing. The hypothesis was that the number of cyclist accidents can be reduced by increasing the visibility of the cyclists. The study design was an RCT with 6793 volunteer cyclists – 3402 test cyclists (with a yellow jacket) and 3391 control cyclists (without the jacket). The safety effect of the jacket was analysed by comparing the number of self-reported accidents for the two groups. The accident rate (AR) (accidents per person month) for personal injury accidents (PIAs) for the test group was 47% lower than that of the control group. For accidents involving cyclists and motor vehicles, it was 55% lower. The study was non-blinded, and the number of reported single accidents was significantly lower in the test group than in the control group. This is likely a result of a response bias, since the bicycle jacket was not expected to affect the number of single accidents. To compensate for this bias, a separate analysis was carried out. This analysis reduced the effect of the jacket from 47% to 38%.

Source: The effect of a yellow bicycle jacket on cyclist accidents

[iansoady]

Of course this wasn't a double blinded trial (where both researchers and subjects do not know into which arm they are recruited which would be impossible anyway) so the behaviour of both may have been influenced by their expectations.

[Hot_Air]

Indeed. The full article highlights this issue and how the researchers sought to address it. Nonetheless, it’s highly informative to have an RCT, not ‘merely’ an observational study.

[Horse]

It's also an occasion to be celebrated of where science supports the blindingly (sic) obvious

Particularly for bikes with larger fairings and screens (and topboxes), the body of a waistcoat will hardly show. And the retroreflective bit that does is, typically, grey*

* Doesn't have to be. Coloured retroreflective material which meets the standards is available. It would also slightly reduce any camo effect.