"Richard J." wrote in message
...
Rob wrote:
"Klaatu" wrote in message
...
What does it mean ?

It's on one of the new double decker busses as you enter
at the front, on the left, under the windscreen.

There is a headlight sign and 1.3 %.

I asked the driver with predictable results.

First correct answer gets a cracker jack pencil.

If u look on any vechile you will find this. its to do with the
aim of the headlights to avoid dassileing othere road uses

Perhaps 1.3% is the percentage of words you spell correctly?
:-)

Seriously, you are right. See official diagram at
http://www.hmso.gov.uk/si/si1989/Uks..._en_28.htm#end

The requirement is specified at
http://www.hmso.gov.uk/si/si1989/Uks...n_9.htm#(4i)i2
See paragraph 12(b).

I wonder what that figure of 1.3% actually *means*. It's a strange way to
specify what is really an angle between the horizontal and the beam. I
presume that 1.3% equates to arctan(1.3/100) or 0.75 degrees. I suppose it's
done like that because the easiest way to check the setting is to position
that vehicle a known distance (eg 10 metres) from a vertical wall and
measure the vertical offset (eg 1.3% of 10 = 0.13 metres) of the beam from
the straight-ahead position of the headlamp.

I notice that the regs don't mention that headlamps usually dip leftwards as
well as downwards - or at least they don't stipluate the amount of
horizontal offset.