When I drop the kids of at school in the morning at 8.20 am, there is a usually a long queue of traffic going downhill (about half a mile long and moving very slowly i.e. slower than I can walk), although there is very little congestion at the top (about five or ten cars, max.).
You might assume that this is because all the commuters are heading downhill (despite that being the direction away from, rather than towards, central London) in the morning, in which case, you would expect to see a long queue uphill on their return journey in the afternoon rush-hour and traffic moving freely downhill.
Far from it. For the first time in ages I happened to be driving up the hill at 5.45 pm yesterday, and there was still a very long queue going downhill, so that rules out that explanation.
Might it be because there is only a mini-roundabout at the top of the hill (and the next set of traffic lights is a good half-mile away) but there is a set of traffic lights at the bottom?
Just askin', is all.
Saturday, 27 June 2009
Traffic lights (10)
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14 comments:
Maybe it's the start of a pilgrimage.
In a 'roundabout' sort of way you make 'light' of a problem, which in one form or another, happens every day, just about everywhere.
Maybe also everyone going downhill all the time but mirrors the general state of the country?
Yup, traffic lights are a pain.
Mind you, so are people who never indicate on roundabouts! The increase in these is hard to explain, but a definite phenomenon...
Traffic lights are analogous to socialistic bureaucratic rationing. They ration road space. Which why they usually create congestion. Roundabouts allow the right priority rule to work well, most of the time. To make them work properly it is soemtimes necessary to put mini roundabaouts in large roundabouts with particularly high one way peak flows.
A better way to deal with many urban junctions is to make them shared spaces with vehicles and pedestrians all sharing the same space. Drivers and pedestrians are forced to make eye contact and experiments have shown that such junctions are safer and flow better.
In essence, like a market, the agents within it know better than any bureaucrat how to use it most efficiently.
If you have pedestrians that need to cross at peak times, you might want to put pedestrian crossing lights up, but persoanlly I would still go for the shared space system. Apparently such engineering also slows down traffic, whilst inceasung flows. It's a win win.
I have become more and more certain that the less bureaucratic rationing you have in any circumstances the better to world works. This applies to automatic rationing systems like traffic control.
BTW this also puts the lie to maximum speed limits increase afety. No, its raod conditions that alter safety. Variable speed limits have been shown to increase flows on the M25 in peak times, so in non peak times they could be removed couldn't they?
Highway Engineering has been hijacked by the LA bureaucracy.
JH, wot? Twice a day?
WFW, don't they make you see red?
JM, nobody indicates on roundabouts any more, except me, who sometimes indicates 'right' just to keep the other drivers guessing.
L, agreed, as to pedestrians, I would just give them right of way, i.e. declare all roads (apart from motorways) to be a giant zebra crossing. And declare all junctions to be a yellow box while I'm at it.
Shared space, my foot!But t'would be more than my foot pulverized. As a non-driver ie,pedestrian,I have to do car drivers'looking for them. They don't see pedestrians, or cyclists, they feel powerful, secure and a massive sense of rightness.Each thinks he is a special case.Guess answer istoo manycars in toosmallspaces.(there is a respectable 'cluster' theory, but can't cite references,I'm afraid)
PatsyH, 'shared space' is one of those mad sounding ideas that works perfectly well in practice. Some towns have tried it.
In fact, the whole idea that pavements and roads and everything are separated up, and everybody is told what to do, is the new idea, which clearly isn't working.
Everything separated...new idea..Large powerful machines 1 per person is also 'new idea'.(Bad idea?) Hence pavements.Though they drive & park on these too.I've heard about shared space & will believe it(as a real solution that's really working)when I see it.
Am realizing belatedly this is libertarian site,judging by tenor of comments
I had to walk to school.
PatsyH, 'Shared space' is not libertarian, it's pragmatarian.
Plus in this case we were talking about the reason for the traffic jam. The mini-roundabout, that leaves it up to drivers to sort it out between themselves, clearly works 'better' than the lights. And, speaking as a pedestrian, it's just as easy to cross the road at the top as it is at the bottom.
You didn't take up my comment about 'traffic clustering'. (my phrase). it has been noted that on motorways you get jams or tailbacks for no apparent reason. A theory is that one person's brake lights go on & a chain reaction occurs. Probably not applicable in this case; you theory sounds the most probable.
PatsyH, the 'cluster theory' for motorways is perfectly valid and is backed up by evidence - such faux traffic jams move slowly backwards at a speed that is proportional to the density of traffic and so on, greater minds than mine have studied it in depth. In the absence of a better explanation, we will just have to accept it as correct.
But that is neither an argument for or against traffic lights.
http://www.amasci.com/amateur/traffic/traffic1.html
Not far from me there is a set of lights at a major junction. Up until about three years ago there were three lanes for this junction - one for left turn, one for straight ahead and one for right turn. Most cars go left or straight ahead. Even at peak times, queues rarely extended beyond 8-10 car lengths and most of those would get across at one change).
Then they decided we needed a cycle lane. So a cycle lane (grotesquely painted green) was installed and the junction turned into two lanes - one for right turn (which hardly anyone uses - because there is another road quarter of a mile back which leads onto the same stretch) and one lane for left turn or straight ahead.
Now the queues extend for around a mile or more, the cycle lane is barely used and the right hand lane is only used by impatient drivers who zoom up the outside of the queue before cutting in leading to frequent incidents of road rage and more than a few accidents.
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