"Tom Anderson" wrote in message
.li...

I was thinking about this a while ago, and i thought that
the best thing might be to use shape - build red lights
with two elements, an inverted triangle and a circle
enclosing it, like an upside-down version of this:

http://www.analyzemath.com/Geometry/...cumcircle2.gif

When you mean 'stop', light both bits; when you mean
'probably stop, but go if nobody's coming', you light the
triangle. The idea here is that the probably-stop light looks
like an illuminated version of the existing 'give way' sign,
which will hopefully trigger the right behaviour in drivers
who see it. And, since it's solid red, the main failure mode
is going to be to mistake it for a circular red, which is fine -
it's always safe to stop at a probably-stop. The downside, of
course, is that you need to build entirely new, and more complex, lights.

And that after a while, people would start mistaking stop lights for give
way lights, which isn't always safe.

All that said, isn't the real solution to make the lights
(or rather, the junction) sensor-controlled, or perhaps
better-sensor-controlled? If the junction knew there
was a queue of cars waiting to go one way, and cars
were only a few a minute the other way, it could just
change its lights to let them through.

I think bicycles fail to activate the sensors, which is one reason why
cyclists habitually jump red lights. Why are these sensors so rare anyway?
Are they very expensive?

Why has Britain never copied the Japanese idea of
having a digital countdown above traffic lights?
Surely it would increase capacity, and also give
drivers free time to have drinks or change CDs
instead of staring at the red light.

Maybe there's a worry that if people know they can go in 1
second, they'll go right now, since it's bound to be safe, isn't it ...

Some drivers do that already. As a driver, I usually watch the traffic
lights for crossing traffic and pedestrians, because they give me advance
warning of when my light will go green.

Incidentally, the other week I saw a car stop at a red light, and then
slowly roll forward at about 5cm/sec until his entire car was over the stop
line. At which point the camera above the traffic light flashed and he got a
100 pound fine and three points on his license. For some reason, that made
my day.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes