OT: Motorway lights one cones... in sync?

[Andy Champ]

M25 concertina is caused when people drive just a little too close. Someone brakes, the person behind has to brake just a little harder...

Andy

[Andy Champ]

Highway code, rule 114:

MUST NOT

• use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders

So when I'm stuck in a jam with the guy in front with his foot on the brake pedal, and the guy behind with his headlights silhouetting my head against the back of the car in front...

... It's a normal evening commute.

Andy

[geoff]

Which, if you add up all those 0.2s ...

[Mike Clarke]

... means they could drive that little bit closer together?

[Andy Champ]

Not physically possible. You cannot reduce the gap below zero. :)

(I recall some years ago I had to get an 11:00 flight out of Gatwick. The weather forecast was appalling. I am worrying about driving around the M25, in the rush hour, in the rain. At this point my mother-in-law, who was visiting, asked me if I was frightened of flying...)

Andy

[RW]

Wrong...That's the M25

[geoff]

In message , RW writes

The M20 is the overflow for when the x-channel ferry is knackered

[Bob Eager]

As I said earlier....the M20 is the *lorry* park.

[The Medway Handyman]

Operation Stack its called. The local on site caterers love it!

800 lorry drivers all wanting a bacon butty :-)

[Skipweasel]

You've not seen my wife parking.

[dmc]

Less fun for us who live in Cheriton though :-(

Must be due one soon, not been one for a few months now (it seems to have stopped being newsworthy now :-()

Darren

[Andy Dingley]

Try it, it's noticeable! I'm running 2 incandescent brake lights and an LED in the centre high-level for just this reason.

My LED bulb review was posted to uk.rec.cars.something a few weeks back.

[Andy Dingley]

I'm not worried about my driving, I'm worried about the low standards of the muppet behind me.

I crossed the Severn at 40mph at the weekend owing to truly foul weather, and I _still_ had a moron hung onto my back bumper. Had to drop to about 25 before they got the hint and overtook.

[Andy Dingley]

No, faster response would _reduce_ this (assuming a constant distance).

[Andy Dingley]

This is unusual for brake light LEDs, but common for larger interior lamps.

Ultra-bright LEDs no longer use the pulsed high-current drives that were common 10-20 years ago. Nowadays modern LEDs (especially white) are driven from a constant current circuit.

To work from 12V car voltages or possibly wide input voltage ranges, the larger multi-chip LED bulbs may use a buck circuit to shift voltages as needed - effectively a tiny switched mode PSU. These are what causes the flashing effect.

It doesn't bother me, but I know it does some people. Probably something that designers should avoid. But then if car light designers paid the slightest attention to ergonomics, VW wouldn't have put the invisible front indicators on the Golf inboard of the sidelights and too close to distinguish them.

[Tony Bryer]

This is the nonsense of speed cameras - they are removing from drivers the idea that they are responsible for setting a safe speed according to the conditions. What we need are cameras that pick up on tailgating, not speed - there was a news story on such an idea a couple of years back. Or, better still, a traffic cop on an overbridge with a video camera: then call in the miscreants for a replay and suitably embarrassing interview. But of course this would cost money, not make it.

[Andrew Gabriel]

There used to be a tailgating detector on the A414 heading up the hill just before the Park Street / M11 roundabout at St.Albans. This was in the mid/late 1980's. It lit up a sign which said (IIRC) "Too Close". The sign could also say "Queue Ahead" when there was a queue over the brow of the hill getting onto the roundabout. Sometime around 1990, the sign stopped working and then the detectors and sign slowly fell to bits. It seemed to work well, whilst the sign worked. I saw people back off from me when they managed to light it up. There was no speed-type camera -- it just lit up a warning sign. I did wonder how it came about in the first place -- I never saw any others and therefore assumed it was experimental.

[<me9]

With a suitable £60 ticket at the end, it could make money.

[Man at B&Q]

Instrument clusters will all be flat panel displays before long.

MBQ

[Man at B&Q]

They are often driven by a PWM waveform to allow dimming.

Not at the frequencies they switch at.

If you can see the strobe effect with the eye, its due to a PWM output driving the LED, either to allow dimming or to reduce power consumption by making use of the persistence of vision, or both, depending on the application.

MBQ