Average Sped Cameras

[derekpara]

Have you ever been caught by one of these cameras ?

I've just come through a section of the M11/M25 with signs warning of 'Average Speed Cameras' and been passed by many vehicles cruising at well over the designated 50 limit. Just wondered if the cameras were fact or fiction.

[pink-kittens]

According to a news report by the BBC it is relatively easy to avoid these average speed camera tickets by simply changing lanes. These cameras are fixed on one lane each
Wouldn't like to try it myself with all lanes travelling at the same speed as you get caught between 2 cameras not the one at the end and beginning, apparently

And yes, I know people who have been caught

[SeaJayPea]

Remember, they are AVERAGE speed cameras. So, if you do 70 mph for the first half of the roadworks and 30 mph for the rest of it, you'd average 50 mph. This is an extreme example, of course, and they sometimes break long sections of work into several stages. You do need to be alert.

I think I read somewhere that they've sorted out the software glitch that stopped them dealing with changing lane.

And yes, I do know of people who've been done in them.

[Milvus]

The lane changing problem was cured years ago. Old cameras worked in pairs along the road the entry camera being connected by cable to the exit cable. Modern cameras send number plate details to a central computer, lane independent, and order independent. So the speed could be measured from set 1-3 and set 2-4 in a long stretch.

[jno]

they should have them along entire motorways.

[jake-the-peg]

Why jno?

Most road deaths don't occur on Motorways

Surely enforcement efforts should be concentrated where they do most good at improving safety putting them on motorways would just make the revenue generators

[EvianBaby]

Yes, they do work. 3 of our employees have been caught by them in the past 6 months.

They are usually only in place for a few miles so it's pretty pointless trying to pull little tricks to avoid it.

[New Judge]

You can prove anything with statistics, so here goes:

1.1% of Britain’s roads are motorways (2,705 of an approximate total of 247,000).

In 2008 there were 2,538 deaths on the roads of which 158 (6.2%) occurred on motorways. That is one deaths for every 17 miles of motorway and one death for every 102 miles of other roads.

So, mile for mile motorways are six times as dangerous as other roads. Put another way, assuming all the deaths result from excess speed (very rash assumption) a camera covering 100 miles of motorway will prevent six deaths whilst one covering 100 miles of other roads will prevent only one.

[jno]

my own answer would have been: because passing laws but refusing to enforce them is a bad thing generally.

Nothing wrong with generating revenue from lawbreakers, either.

[grasscarp]

I read that about changing lanes, so always do. I am afraid to say I dont stick strictly to the 50 in them (if it is safe to do so) and have never got done. I am lucky though as I have never been caught by any camera, and the only time I was pulled over for speeding it was a BMW that miraculously turned itself into a police car.

[joko]

i think speed alone means that whilst accidents may not happen as often on motorways, when they do they are pretty catastrophic and can end up with multiple fatalities - unlike on normal roads when usually only one or 2 people are injured, often minor.

[EvianBaby]

"So, mile for mile motorways are six times as dangerous as other roads. Put another way, assuming all the deaths result from excess speed (very rash assumption) a camera covering 100 miles of motorway will prevent six deaths whilst one covering 100 miles of other roads will prevent only one."

I would agree that would be a very rash assumption New Judge. It is impossible to say that a camera would prevent 6 deaths per year. Why could a fatal accident that happened at 80mph also not happen at 70 or even 60.

[joggerjayne]

The daft thing about average speed cameras on motorways is that a lot of them have service stations between the camera points.

Say the stretch of motorway between cameras is 10 miles ...

And the speed limit is reduced to 50 mph.

At an average speed of 50 mph, you will take 12 mins between the cameras.

If you stop at the service station for 6 minutes, and get a coffee, or petrol ...

... then you can drive the 10 miles at 100 mph, and you'll also take 12 mins.

[New Judge]

Indeed, EB. My conclusion was somewhat haphazard and a bit tongue-in-cheek. I was just trying to illustrate that it is not so straightforward as to say, as jake did, "Most road deaths don't occur on Motorways"

[bamberger]

"So, if you do 70 mph for the first half of the roadworks and 30 mph for the rest of it, you'd average 50 mph."

Not so-supposethe roadworks were 42 miles long.
21 miles at 70 mph takes .3 hours =18 mins
21 miles at 30 mph takes .7 hours =42 mins
Total distance 42 miles, total time 60 mins average speed 42 mph