I remember back in the late 1990's Volvo or Saab was exploring supplimental UV driving lights that could project farther, yet didn't blind oncoming drivers because the wavelength was invisible. The idea was to be able to enhance signage and reflectors that had a flourescent quality added to them, as well as whatever naturally occuring flourescent content was out there. These UV lights were also supposed to barely scatter in fog. The problem with the fog, I think, is that objects that flouresce will reflect the UV light back at a different, visible light frequency that would then be subject to scattering by the fog.

ANYWAY, I was thinking about this after some recent night time encounters with bike-ninjas and darkly dressed, non-reflective jay-walkers. I see modern LED UV flashlights for forensic work and for finding and cleaning cat-pee. I didn't see any lumen ratings, but a couple of units mentioned a 15-20 foot range.

My question is, is there an effective supplimental UV light source that could be used on the bike for night riding, or is this a case of "if it worked, it would exist and be in use already?"

A "UV light" would scare away the masses since they think that all UV causes skin cancer. Besides, normal lights do perfectly well at lighting up reflecting signage much further than the light actually projects. UV light generally passes through the air with no problem (I use a UV laser at work) but you may find some weird compounds that fluoresce under UV light. Maybe some fertilizer or something. I don't really see an advantage of using a UV light over a normal light. I don't think the fluorescence caused by UV would be strong enough to see outdoors from any distance. The orange tinted glasses that come with UV light kits are used to block a bit of the visible light out to make the fluorescence more visible, therefore it's doubtful that you'd see it without such a device. Also the light sources that CSI investigators use are tuned with visible and IR bands to block out background noise from normal clothing/sheets etc.

The main problem I see is that the visible light from your normal light would make any fluorescence that you see nearly invisible.

Yeah, that's probably why they don't use them for cars. Thanks for the input!