Being seen in the dark: reflectors, hi-vis vest, light

Fluorescent colours have a special trick: they take in invisible UV light from daylight and give it off again as visible light. That is why they look brighter than normal colours and seem to glow in daylight and at dusk. In complete darkness, with no light falling on them, they help very little.

Reflectors work differently. A normal mirror throws light off at an angle, depending on how you hold it. A retroreflector, by contrast, sends light back almost exactly where it came from – using many tiny glass beads or prisms. For a driver this means: the light from their headlights comes back from your vest straight to their eyes, and you light up brightly.

Your own light is the only thing that always works, even when no headlight is pointing at you. Someone carrying a lamp is also seen by people who have no light themselves, such as other pedestrians during a power cut.

Combine the three helpers: fluorescent colour for daylight and dusk, reflectors for night when vehicles come, and your own lamp for every situation. Do not rely on reflectors alone where there are no headlights, for example on farm tracks or during a power cut in town.

Reflectors on parts that move are particularly effective. Reflective bands on ankles and wrists show a typical walking motion that helps drivers recognise more quickly that this is a person and not a post or sign.

On roads without a pavement, walk as local rules require – in many places facing oncoming traffic, so that you see vehicles coming. In a group, walk in single file at the edge, and at least someone at the front and someone at the back carries a light. Whether and how this is regulated differs by country – check local rules.

A hi-vis vest makes you more visible, but it does not protect you from an impact. Being on the carriageway or right next to it remains life-threatening. After a breakdown, the most important thing is therefore to reach a safe place quickly: behind the crash barrier or well away from the road.

Keep the vest within reach inside the vehicle, not in the boot. Put it on while still in the car and then, if possible, get out on the side away from traffic. Do not stay sitting on the hard shoulder next to the traffic.

From your safe spot, call the breakdown service or, if people are in danger, the local emergency number (112 in the EU). Whether hi-vis vests must be carried in vehicles, and how many, is set by each country – check the rules, especially before driving abroad.

The way to school in winter: in the morning and afternoon it is often dim or dark. A bright jacket, reflectors on the school bag and reflective bands on arms or legs make children visible to drivers much earlier. Older people benefit in just the same way.

Power cut in town: when street lights and traffic lights fail, it is suddenly very dark and drivers are unsure. A small lamp and reflectors on your clothing help you be seen on the way home or to a help point.

In the field during a search: reflective elements on jacket and pack can help searchers with lamps spot you at night. The principle is the same as in road traffic: if you want to be seen, you need contrast and light.

The basic kit is cheap and light: a hi-vis vest in the car, reflective bands and a small lamp in your jacket or pack. Many jackets, packs and shoes already have reflective strips; look out for them when buying.

Reflective material wears out over time. Frequent washing, abrasion and dirt can reduce its effect. Check your vest and bands now and then: do they still light up brightly when you shine a torch on them in the dark from eye level? If not, replace them.

A simple test for the whole family: one evening, take turns standing by a dark path in different clothing while someone shines a lamp from some distance away. You will see how big the difference is between dark clothing and reflectors.