Street Legal

"Der Lichtkegel muß mindestens so geneigt sein, daß seine Mitte in 5 m Entfernung vor dem
Scheinwerfer nur halb so hoch liegt wie bei seinem Austritt aus dem Scheinwerfer." 

"The light cone must be so angled that its middle at a distance of
5 m from the lamp is half as high as at the exit of the lamp."

I have a lot of experience riding when it is dark on my commute to work.  Unless you are alone in the woods you will find a bright symmetrical lens mtn bike will annoy pedestrians as well as car drivers. The bean from a symmetrical lens is blinding to oncoming traffic, either pedestrian, other cyclists, or other cars.   A mtn bike light on a bike path can even lead to an accident since the oncoming people are so blinded they cannot judge where you are relative to the path.   

A street legal light blocks light above a certain point on the horizon, just like auto head lights do.  A symmetrical bean will light above the horizon as well so you can see branches.   A symmetrical beam is more comfortable to ride with in the woodsbut it is extremely dangerous when there is oncoming traffic involved. 

For this reason I do not recommend the Alien Eye for street or commuter use on bike paths.  Once you are on the receiving end of a bright symmetrical Mtn. bike light as a cyclist you will know the danger involved with riding with such a light.