What are the knobs under pedestrian crossings for?

[ecalverley]

On the new style pedestrian crossings (I think they're called Toucan crossings) there is a small black knob on the underside of the "press button & wait" box. This knob rotates but seems to have some friction/momentum about it. It just keeps turning (Once you know it's there you just have to!). Any info on what it's for would be appreciated!

[Mortartube]

I've been told that this is so that blind people know when it's safe to cross the road. Whether this is the real reason or not, I am unsure, but it makes sense to me.

[derbyram]

if mortartube's answer is correct, just how many blind road traffic accident victims do you reckon you are responsible for ecalverley?B>?

[ecalverley]

I don't think it's for blind people as it doesn't do anything different when the lights change to green - it just turns. I did wonder if it was a volume control for the beeping but I didn't notice that change.

[ecalverley]

Doh! If I hadn't been fiddling with it before the lights changed I would have noticed that it starts turning when green man shows. My apologies to Mortartube for not believing. Here's a nice site that explains it and also explains the difference between Zebra, Pelican, Puffin & Toucan crossings: http://www.travelwise.org.uk/safe/tech_pedestrian.shtml :-)

[IndieSinger]

*Comedy Answer*
They're usually just waiting to cross the road to hang around outside McDonald's/Weatherspoons.

[Mattk]

surely this must be for deaf/blind people ? as if a blind person was at the crossing he would simply hear the beeps ! the knob must be for people who are also deaf

[ecalverley]

Not just for Deaf blind people. Imagine the situatio of crossing a dual carridgeway with separately controlled crossing on each side. A blind person in the middle hears the beeping but doesn't know which side it's for. Apparently some crossings like these are ONLY being fitted with knobs - no beeps at all.