"Andrew" wrote in message
...
On 15/09/2019 09:21, ARW wrote:
Highway code rule 114

You MUST NOT

use any lights in a way which would dazzle or cause discomfort to other
road users, including pedestrians, cyclists and horse riders

Have all modern cars with daytime running lamps been exempted
from this then ?.

It's less of a problem for DLRs because they are at the front of the car so
an oncoming driver only sees them for a few seconds as they pass the car
with DRLs. Brake lights are more of a problem because once you are behind a
car in traffic, you will see his brake lights all the time they are on. If
I'm stuck in traffic at night, inching forwards in a traffic jam, I find I
have to shut my eyes as soon as I've stopped, to give me some night vision
for when the car in front starts moving again.

DRLs also have the advantage that they dim at night (eg when the
side/headlights are on) so they are only as bright as they need to be for
the ambient lighting. Brake lights, on the other hand, have to be bright to
be seen during the day and remain at that brightness at night. I imagine now
that cars are starting to use LEDs rather than filament bulbs, we will see
brake lights being dimmed at night, though it will need to be based on
measuring ambient light rather than controlled by the light switch because
you still want the brake lights to be bright if you are driving with lights
on in rain/fog during the day.