Ever feel concerned riding home in the dark that a driver might not see you on the roundabout? So were these bike lovers from a company in San Francisco, which is why they designed a bicycle that is 100 per cent retro-reflective, perfect for cycling home safely after a fun night out.

The Lumen bike involves a patented innovation that returns any light that hits the bike’s frame and wheels directly back to the source.

Retro-reflection

By day, the Lumen is a slightly iridescent deep charcoal grey, while by night its frame and rims glow in reflected light. It doesn’t use batteries, simply the light coming from nearby cars, streetlights and even moonlight.

Nor does it always look the same. Other sorts of reflection bounce, scatter or diffuse the light hitting it, whereas retro-reflections returns light directly to its source. As retro-reflection works by reflecting light back to its source, creating a signal that is brighter and more intense.

As light enters each of the hundreds of thousands of microscopic spheres painted on the bike, it deflects right back to the source. This effect is known as "cat’s eye" and is visible up to 300 metres.

Development of the Lumen

The brains behind the Lumen were inspired by hyper-reflective street signs, posing the question "Why can’t this technology be applied to a bicycle frame?"

There was, however, a good answer to that: retro-reflective solutions were then only available in a 2D format, applied as stripes on the road or the back of a sign.

In order to coat a 3D frame, the developers turned to a company that develops technologies to apply reflective coatings to 3D surface, including the patented powder coat used on the Lumen.

Company behind the Lumen

Mission Bicycle Company has been around in San Francisco for five years, aiming to build the most innovative and beautiful city bikes. Their bikes are built one at a time by hand.

All the Lumen bikes are built with frames made from hand-welded double-butted chromoly steel and guaranteed for 50 years. There are three designs: one single-speed and two geared bikes.

Their Kickstarter project has already made well over its aim, so the bikes should be ready for delivery later this year.