In our village we have recently had a new set of traffic lights installed and as part of these, there seems to be various sensors pole mounted before you reach the lights.
Yesterday I queried one aspect of these with the council, namely the split time on them between one light going amber to red, and the other going red to amber which may result in a couple of drivers meeting if they both go through on amber.
Anyway attached is a reply I received which impresses me as it would seem that these lights are totally controlled by traffic!
X Cross has the most up to date traffic signal system it is possible to install in the United Kingdom, having a microprocessor at its heart. It uses a technology called MOVA (Microprocessor Optimised Vehicle Actuation) which uses the detectors (8 off) at the site to continuously learn the traffic patterns and queues which occur at the junction. As such there are no defined timings installed as there would be at a traditional set of signals, instead the detectors measure both the speed of approach of vehicles and the queue lengths and looking at all three approaches adjust each individually and continuously to optimise the traffic through the junction. In this way there are savings in the time which would normally be lost by changing from approach to approach every 90 secs whether required or not as happened in the past. This time is then given to the heaviest traffic flows.
There are also detectors which measure whether there are vehicles waiting to make a right turn into X Street and if so then the Right turn filter arrow is used as and when required, but again it is only called if there are more than 2 vehicles waiting.
Because of the above the only conflict can be caused by drivers failing to observe the signals and going through either red/amber or amber depending on which approach they are on. As you can see it is not possible to just go out and add time into any particular part of the sequence as that would remove the ability of the microprocessor to make the most efficient use of the available time.
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Sounds good.
Hope it works for pushbikes - there used to be one with motion sensors which would never recognise that I was waiting - almost made me join the red light brigade!
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Haha,
When I was a learner I once approached a set of traffic lights which detected approaching cars by means of a rubber strip set into the road surface (I mean a proper rubber strip, not the filled-in grooves currently in use) and stalled when the signals changed to green.
By the time I had got it started the lights had changed back to red, I then had to wait for nearly 10 minutes until another car approached from behind to trigger the lights again!
Dave TD
Edited by Dave_TD {P} on 24/04/2009 at 21:37
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Many years ago there was a system which did the same thing. It was called a Policeman on point duty.
tinyurl.com/d7mj2k
At changeover time the "new" policemen were marched by a sergeant, military style, from the police station round a route, stopping at all the junctions where the "new" cop peeled off, and the "old" one took his place and when changeover was complete all the "old" ones marched back to the station.
somehow red amber and green lights just don't have the same charisma.
I think my brother has the picture of our dad doing this.
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Couldn't find reverse either, Dave?
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It was quite probably only my second or third day behind the wheel IIRC, practising in my dad's Escort. I was on a relatively minor road at its (downhill) intersection with an A-road, in the days when there was much less traffic around in the evenings (no late-night opening supermarkets in those days). I'm sure if reversing were a realistic option I'd have done so.
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a Policeman on point duty. tinyurl.com/d7mj2k
That photo brought back memories, I used to wear the same gloves and armbands when I worked a traffic point in Manchester City Centre in 67/68. It was at the old Cromwell statue on Deansgate and I used to work hour on/hour off with a bobby who had joined in 1936. He was a real old time copper, 6ft 3ins tall, never drove a car, cycled to work, in uniform, with his cape draped over the handlebars from his little terraced house just off the division. I don't think they could get rid of him ! Real 'Blue Lamp' stuff.
I enjoyed it though, great feeling of power to control all the city's through traffic.
Ted
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Reminds me of one of the great Don McLean's lyrics:
"You remember young Diddy McClaren, of course
But he's over here with the rest of the force
I saw him one day as he stood on the strand
Stopped all the traffic with a wave of his hand
As we were talking of days that are gone
The whole town of London stood there to look on
But for all his great powers, he's wishful like me
To be back where the dark Mourne sweeps down to the sea
[ Mountains O'mourne Lyrics on www.lyricsmania.com/ ]
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Lovely...
Young Peter O'Lachlan in my copy.....
There's beautiful girls here, oh never you mind,
With beautiful shapes nature never designed,
and lovely complexions all roses and cream.
and O'Lachlin remarked with regard to the same.
'That if at those roses you chanced for to pick,
the colours would all come away on your lips.'
So I'll wait for the wild rose that's waiting for me,
where the mountains of Mourne sweep down to the sea.
Ted
BR music section.
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