Very bright headlights

[i6941tb@gnn.com]

Hi, listers!

I was coming back from work late Friday evening when I saw a pair of
extremely bright headlights (but not blinding, though), that stood out
in the oncoming train of headlights. They were nothing like I've seen
before. Unlike good high power Halogens, which are absolutely white
(like mine euro- H4s) those were at least two times brighter and had a
very distinct bluish hue to them. The car that wore them was a brand
sparkling new 500sel.
What was that? Some kind of an exotic gas discharge lamp (perhaps Xe,
Ra, Cr or Hg vapour filled)? 
Can fellows from across the pool shed some light on it? Tom, Hans,
Phil...?

Thanks,

Igor