Two wheels: being seen, and not being taken
On a bike the two risks arrive together — being hit because nobody saw you, and losing it while it is parked.
The collision records show how much of the harm in each area happens in darkness, and how much of that happens where there is no street lighting at all. That second figure is the one that decides whether reflective material is enough on its own. Theft is the other half of the same trip: most riders lose more nights to worrying about where the bike is parked than to the ride itself.
Why does being seen after dark come down to more than dark clothing?
Retroreflective material returns light to its source, so a driver's headlights pick it up at roughly three times the distance of dark fabric — at 30mph that is most of the stopping distance. It is the cheapest intervention available and the one with the largest effect per pound.
What it does not cover. But reflection needs a light already aimed at you. On an unlit road, or approaching a junction from the side, there may not be one — which is what the dark-and-unlit share for your area is telling you.
It is parked. What rating do I actually need?
The grade your insurer specifies, in the category that matches your vehicle. Sold Secure attack-tests within categories, and the thresholds differ — a motorcycle Gold is a harder test than a bicycle Gold. Reading only the colour on the box is how people end up under-locked and, at claim time, outside their policy terms.
What it does not cover. And a rating is a time, not a guarantee. What the bike is locked to matters as much as the lock, and the lock should never rest on the ground.
What stops it being wheeled away while I am not there?
A disc lock immobilises the wheel, and the alarmed version adds noise at the moment of interference — which matters because most opportunist theft depends on nobody looking. The rule every rider learns the hard way is that the reminder cable is not optional: riding off with a disc lock fitted is how forks get bent.
Why this page exists
Visibility advice is usually a slogan rather than an explanation, and lock ratings are quoted without anyone explaining that a Gold for bicycles and a Gold for motorcycles are different tests.
Written and reviewed by Stephen Hall, Data lead, Swift Assist, from official DfT collision records and police.uk vehicle crime data. The steps above link to our own guides, which earn us nothing. Those guides then link on to retailers, and where they do we earn a commission if you buy, at no extra cost to you — each guide says so before its links. The sequence above is written first; links are added afterwards, and where a step is not worth buying we say so. How we work.
The other sequences
Stopping a keyless car theft, step by step
A modern car theft is three actions in sequence. Each defence blocks one of them.
Read more →If it is taken anyway: tracking, marking and recovery
Prevention can fail. What decides whether you see it again is what was fitted beforehand.
Read more →Vehicle crime where you live
Police street-level records by town, refreshed monthly.
Read more →Every guide
Each defence matched to what it actually stops.
Read more →