Enter the Hövding airbag for cyclists. We'll explain it more fully after this, big-budget film we made about it. Check out that acting.
The Hövding charges via USB (you get about nine hours of use from it, with an audible warning sounding when you're running short of charge) and is "armed" by zipping it up fully and clipping the zip toggle to the right hand side.
The neckbrace-like collar contains sensors that tell it when you're in a shunt (sudden and catastrophic deceleration or acceleration, the sensation of hurtling through the air, etc). It's calibrated so as not to go off just because you've mounted a tricky curb, or are showing off how efficient your new disk brakes are.
An independent test by Swedish insurance company Folksam found "the chances of a serious head injury were reduced by over 90% when wearing a Hövding, in a collision at 25kph." That's because of the support it instantly provides to your neck, preventing whiplash and worse, as well as the protection it offers your head. Impact protection is "3x better" than that of a helmet, and potentially even more importantly, the Hövding also greatly reduces the effects of G force as you fly over the handlebars shouting, "Oh crikey!"
It's an incredible bit of engineering, but it comes at two costs. One is that you have to wear, effectively, a sort of high-fashion, zip-on neckbrace. This seems like both a style no-no, and also rather uncomfortable in hot weather, although the weight is kept low.
The other cost is its literal one: £249. Should you have to deploy your bag, you can buy a replacement at a reduced rate. Hövding also reckons that some insurance companies will cover the cost of replacement, as with helmets. It also notes that a black box recorder within the collar, "records 10 seconds of data on the cyclist's movement patterns from an accident. In some cases the data from an accident is interesting and valuable to us in our on-going development work."