Proximity-sensing bike tail light warns encroaching drivers
A large percentage of automobile-bicycle collisions occur when a car hits a bike from behind. The UK-designed SureLight bicycle tail light was made with this in mind, as it actually warns motorists when they're getting too close.
Featuring a water-resistant body that's milled from a single block of aircraft-grade sandblasted/anodized aluminum, the SureLight automatically powers up when attached to an included magnetic mount on the bike's seatpost. Its array of 22(!) red LEDS then remain steadily illuminated until the light is pulled off again.
As is the case with many other modern bicycle tail lights, the SureLight also contains an accelerometer that detects when the bicycle starts suddenly slowing down. When this happens, the red LEDs temporarily get brighter, serving as a brake light.
Additionally, however, the SureLight also incorporates a rear-facing proximity sensor. When this device detects that a vehicle behind the bike is getting dangerously close, it triggers an additional six orange LEDs to flash as a warning. The car-to-bike distance at which it kicks in varies with the car's rate of deceleration – we're told that it has a maximum detection range of 4 meters (13 ft).
In regular "cruising" mode, the SureLight puts out 200 lumens over a 120-degree viewing angle. One microUSB-charge of its lithium battery reportedly ought to be good for eight hours of runtime.
Should you be interested, the light is currently the subject of a Kickstarter campaign. Assuming it reaches production, a pledge of £60 (about US$77) will get you one – the planned retail price is £100 ($128).
Potential backers might also be interested in Garmin's Varia Radar system. It includes a tail light that flashes more rapidly when cars are closing in from behind, along with a handlebar-mounted unit (or a smartphone app) that warns the rider. That said, at a price of $199.99, it's also more expensive.