I think you might find that the really bright lights you find on mountain bikes are actully HID rather than LED, though there are high powered LED ones out there too. For single track rides at speed at night I'm sure they are great but I have to agree all the ones I've seen on the roads are needlessly dazleing - I guess some bikers feal for years they have put up with being blinded by cars who can't be bothered to dip their lights so are giving payback?
The HID problem is actully a big personal beef I have. Your BMWs and Audis with their self cleaning, self leveling (you need both if you have HID) setups I find on the hole alright though they are bright if you are unlucky enough to meet one cresting a hill infront of you. Whats the problem is these so called conversions for halogen lights. The owners often think they are super bright as they give more forground light (a bit like driving with front fogs on seems brighter though it can actully make long range vision harder) but the rest eather isn't sent where its needed and worse into oncomming faces. This is the best site I've found on the science behind why they are crap and ilegal...
http://www.danielsternlighting.com/tech ... sions.html
...I think its written for an american audiance, and they do have different lighting requirements to the rest of the world but though they choose to use poorer headlamp design light is still bound by the same laws of phisics that it is here so its still pritty valid.
I don't agree [as Clive has stated] that modern cars are not bound by as stringent rules to lighting as they once were, I'd say it was more so, partly as they tend to push technology more. The reg is called something like ECE48 and covers everything in great detail, all proper car lights have an E marking with a number telling you which country passed it (E1 is Germany and E11 is UK so that covers most you'll see on a VW) along with marks to say how it complies. The problem however I think is mainly the aftermarket addons, as I said with the fake HID setup. What some people with these setups don't seem to realise is that if you have a set of HID halogen lights without all the proper stuff and you meet a VOSA spot check, your jeurny is over as they'll impound your car! With the number on the roads now I think they need to do it more often.
I'd agree that the use of LED for marker bulbs on a vehicle is only of benifit power consumption whise then the engine is off, their incresed durability is the other bonus. For signaling stuff like brakes or indicators the power consumption is irelivent, though the durability remains and the speed of turn on is a plus. I'm with you though Titus A Duxass, Crack out the Carbide...
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http://i40.photobucket.com/albums/e224/ ... Medium.jpg[/img]
(Actully the stinky doesn't work, but the parafin lamp is fine. Don't play with the maglite though, its got an LED conversion

(I've got lots of them))