knowledge - A strange sight in London

While travelling in London, I noticed something strange.

I saw some numbers which appeared to be counting up but which then switched to counting down. Later on, I saw the same thing, but the numbers counted down only.

Questions:

• How was I travelling in London?


• How do you explain what I saw?

Hints:

This is a real phenomenon that anyone might see in London.

London is relevant to the question.

If I'd kept a low profile, I wouldn't have seen this.

Further hint:

What I saw might possibly be seen in other cities in the world.

Cryptic clues to what I was looking at (clues don't include definitions):

Number of dwarfs split up (5, 7)
Not many cars around (7, 5)

Extra cryptic clue following on from the ones above:

Ends cut off - that's peculiar! (4)

And here's a riddling hint for the means of transport:

China in her hand. China in her hand. (6, 6)

Another cryptic clue:

Music genre which might feature The White Stripes (6, 2, 3, 4)

Answer

I think the answer has something to do with a

Seven-segment traffic light countdown timer which show people how long then have left to crossword the road after the green person - for safe to cross - has gone.

How was I travelling in London? How do you explain what I saw?

You may be on foot waiting about to cross a road. These countdown timers are a 7-seg display .

To explain the initial 'appeared to be counting up', and I'm punting here, when first switched on they show all segments lighting-up and show as 8, when display the expected 9, 8, 7, ... 3, 2, 1

Once warmed up they correctly just show the countdown 9, 8, ... 2, 1.

Hints:

They have been introduced to a number of pedestrian crossings in London.

If you'd kept a low profile - say used the Underground/Tube - you wouldn't have seen this.

Cryptic clues:

Number of dwarfs split up (5, 7) → Seven-segment [from seven dwarfs and to segment]
Not many cars around (7, 5) → Traffic light

Extra cryptic clue: Music genre which might feature The White Stripes (6, 2, 3, 4)

Middle of the road

I'm still intrigued and outfoxed by the crux of this puzzle. I think the Hood (good cryptic answer from TwoBitOperation may be the traffic light hood obscuring part of the display) - but I can't get it! Hope someone does!