Volvo and a start-up made Life Paint – a wash-off reflective spray for bikes. The invisible spray covers anything in reflective particles and glows at night. It contains powder-fine reflective particles designed to react to a car’s headlights, alerting drivers to the presence of cyclists in the dark.

The paint is invisible in daylight, but in the dark it reflects light in the same direction as the light source to illuminate the objects it has been sprayed on.

Volvo’s reflective paint sells out: Spray-on ‘light’ is a hit with cyclists [Daily Mail]