Wasn't it Les Hemmings who wrote:

Well, LED's only work with one polarity (all diodes work like a one way
valve, letting current flow one way but not the other) so on alternating
current they will flicker at the same frequency as the mains (50 Hz in the
UK i think) which means there are 25 periods of darkness per second.

I'd guess that they'll probably use flicker-free LED lights for street
lighting. Such things do exist. Some people (e.g. me) find the flicker
from LEDs extremely annoying. I find it painful to look at the new LED
traffic lights that have been installed around here, and would go
bananas if whole streets were lit that way.

By the way: 50Hz would mean 50 periods of darkness per second, not 25.

--
Mike Williams
Gentleman of Leisure