entering average speed zone (50mph) at 60mph

[maverickdrives]

The initial message was deleted from this topic on 29 December 2020 at 20:34

[Gingerbread Man]

There's normally a built in tolerance too I believe, I think you'll be fine.

[veevee]

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

[speedking31]

veevee said:

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

Not correct. Say the section is 180 miles long, you do the first half at 90 taking 1 hour, and the second half at 10 mph taking 9 hours. Total distance = 180 miles in 10 hours, average = 18 mph.

You have to consider the time, not the distance. You could actually do the first 90% at 90 and the last 10% at 10 mph to achieve the average speed :thumb:

[CharlieBangBang]

The problem with 50mph average speed zones is that they start prosecutions at a minimum average of 57mph. HGVs are restricted to 56mph so knowing both of these HGV drivers proceed with their foot to the floor at 56mph and they come into conflict with other drivers at an indicated 50mph which is always much slower than 56mph for an HGV on the limiter.
Professional drivers eh?

[Engineer1]

speedking31 said:

veevee said:

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

Not correct. Say the section is 180 miles long, you do the first half at 90 taking 1 hour, and the second half at 10 mph taking 9 hours. Total distance = 180 miles in 10 hours, average = 18 mph.

You have to consider the time, not the distance. You could actually do the first 90% at 90 and the last 10% at 10 mph to achieve the average speed :thumb:

you are also forgetting that in that first section if you pass through two cameras your speed could have been recorded.

[Riley Blue]

Don't average speed zones have prior warning signs to enable approaching drivers to adjust to the appropriate speed?

[covboy]

Engineer1 said:

speedking31 said:

veevee said:

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

Not correct. Say the section is 180 miles long, you do the first half at 90 taking 1 hour, and the second half at 10 mph taking 9 hours. Total distance = 180 miles in 10 hours, average = 18 mph.

You have to consider the time, not the distance. You could actually do the first 90% at 90 and the last 10% at 10 mph to achieve the average speed :thumb:

you are also forgetting that in that first section if you pass through two cameras your speed could have been recorded.

I think speedking was just trying to give a theoretical example with simple maths rather than a practical setup. Although you are correct, there could be more than a “start” and “finish” camera with numerous intermediate ones which we have no way of knowing which ones are linked.

[Dicky Knee]

I think they only record the time you entered the zone and the time you leave it. So they know the time it has taken to cover a specific distance and calculate the average speed from that. They are only a timing device an not a speed camera so you will be fine.

[theboyfold]

CharlieBangBang said:

The problem with 50mph average speed zones is that they start prosecutions at a minimum average of 57mph. HGVs are restricted to 56mph so knowing both of these HGV drivers proceed with their foot to the floor at 56mph and they come into conflict with other drivers at an indicated 50mph which is always much slower than 56mph for an HGV on the limiter.
Professional drivers eh?

Yep. I stick my cruise control to 50mph in the average zones, so often end up boxed in by trucks. This is worse around the M25 towards Kent where you have foreign trucks that work to their own rules...

[Alpinestars]

veevee said:

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

That's 18 mph isn't it

[andyiley]

There's an echo in here!

in here

in here

in here

[CharlieBangBang]

theboyfold said:

CharlieBangBang said:

The problem with 50mph average speed zones is that they start prosecutions at a minimum average of 57mph. HGVs are restricted to 56mph so knowing both of these HGV drivers proceed with their foot to the floor at 56mph and they come into conflict with other drivers at an indicated 50mph which is always much slower than 56mph for an HGV on the limiter.
Professional drivers eh?

Yep. I stick my cruise control to 50mph in the average zones, so often end up boxed in by trucks. This is worse around the M25 towards Kent where you have foreign trucks that work to their own rules...

Correct and don't forget that if you set your cruise control at 50mph from your speedo you will be travelling below 50mph too.

[Skodaku]

CharlieBangBang said:

The problem with 50mph average speed zones is that they start prosecutions at a minimum average of 57mph. HGVs are restricted to 56mph so knowing both of these HGV drivers proceed with their foot to the floor at 56mph and they come into conflict with other drivers at an indicated 50mph which is always much slower than 56mph for an HGV on the limiter.
Professional drivers eh?

Thank you Sir. You have just explained something that has puzzled me for ages; why, when I'm being a good guy in a 50mph average zone do I invariably have some Scania/Volvo/MAN/Merc etc welded to my rear bumper ? I'm generally sat at an indicated 52 or so as I know my speedo calibration at various speeds, but it now makes sense.

Next.

[Cooperman]

The SPECS units are not speed cameras, they are clock-cameras. All they record are the registration number and the exact time. This is electronically compared with the time at which the next camera in the timed section is passed, the distance between the clock-cameras is divided by the time taken to give the AVERAGE speed. Prosecution may result if the average speed in in excess of the posted limit on that road by more than the speed tolerance.
So in a 60 mph limit with SPECS clocks, you could pass the first camera at 100 mph, or more if you wished, then stop for a cup of tea beside the road, and pass the second one at an equally high speed with no risk of prosecution by the SPECS system.
One thing no-one has mentioned is whether a police car following a vehicle through a SPECS equipped section can also prosecute for exceeding the limit, bearing in mind that one cannot be prosecuted more than once for a single offence.

[Red Devil]

speedking31 said:

veevee said:

It's an average speed zone, you can enter and drive half of it at 90mph, as long as you do the other half at 10mph.

Not correct. Say the section is 180 miles long, you do the first half at 90 taking 1 hour, and the second half at 10 mph taking 9 hours. Total distance = 180 miles in 10 hours, average = 18 mph.

You have to consider the time, not the distance. You could actually do the first 90% at 90 and the last 10% at 10 mph to achieve the average speed :thumb:

Somewhat irrelevant either way given that the average can be calculated between any two SPECS cameras. 90mph between the first two could be enough to see you facing prosecution.

[jelley]

The average speed cameras take an average speed over 3 camera's, it doesn't matter how long the stretch
is,

[covboy]

jelley said:

The average speed cameras take an average speed over 3 camera's, it doesn't matter how long the stretch
is,

Where did that come from ?

[SV8Predator]

covboy said:

Where did that come from ?

He just made it up.

[roofer]

Cooperman said:

The SPECS units are not speed cameras, they are clock-cameras. All they record are the registration number and the exact time. This is electronically compared with the time at which the next camera in the timed section is passed, the distance between the clock-cameras is divided by the time taken to give the AVERAGE speed. Prosecution may result if the average speed in in excess of the posted limit on that road by more than the speed tolerance.
So in a 60 mph limit with SPECS clocks, you could pass the first camera at 100 mph, or more if you wished, then stop for a cup of tea beside the road, and pass the second one at an equally high speed with no risk of prosecution by the SPECS system.
One thing no-one has mentioned is whether a police car following a vehicle through a SPECS equipped section can also prosecute for exceeding the limit, bearing in mind that one cannot be prosecuted more than once for a single offence.

This being correct, the ones on the M25 northern section don't work then.