A few friends and I have been working on an idea to help prevent motorcycle rear collision accidents. We are building a device to help warn riders when a vehicle is approaching too quickly from behind, as well as help catch the approaching vehicle's attention when triggered and encourage them to slow down.
In a nutshell, it works like this. On the one hand, a mounted sensor on the back of the bike will detect when a vehicle is approaching to quickly, then notifying the rider via a warning light from the dash/gauge cluster powerful enough to be noticed without taking your eyes off the road. On the other hand, once the device is triggered, the emergency lights (or additional warning lights attached on the bike rear) will activate, helping to catch the approaching vehicle's attention and encourage them to slow down.
If you have an opinion on this, I'd be happy to hear it. Also, we're mostly concerned with getting your opinion on the idea in general - don't worry about the technical aspects as of yet.