M1 Speed Cameras near Hemel Hempstead

[GuitarPlayer63]

be careful, there is a growing use of Average Speed cameras on motorways, so I can only guess the "Warp 1 approach" will be rumbled (damn!) and there are no signs to say they are measuring average speed.

[V8 Fettler]

I've observed hadecs and gatso flashing away merrily at everyman and his dog on the M25 and the M1 over the last couple of years, although I've convinced myself it's becoming endemic just recently, enough to make me jittery at a GPS confirmed trundling speed of 78.

Don't forget to update.

[V8 Fettler]

Steve vRS said:

hora said:

Whats the safe 'limit' with them turned off. I might be driving down to London this weekend.

IF they are switched on when the variable limit is NOT operational, I can confirm that they flash at 85mph but not at 70mph. Other cars were passing me at what may have been 80mph and they were not flashing either.

Steve

>14 days. Safe?

[Phatboy317]

R0G said:

Simple answer is to stick to the limit and the issue goes away ... yes?

If it were that simple and straightforward then everyone would do it, and people like you would no longer have your favourite sound bite and therefore you would be at a loss for words.

[Phatboy317]

littleredrooster said:

Quite the opposite is actually true; maximum capacity on a motorway is reached when the traffic is moving steadily at a speed somewhere between 30 and 40mph surprisingly.

Care to explain exactly how that works?

[Steve vRS]

V8 Fettler said:

Steve vRS said:

hora said:

Whats the safe 'limit' with them turned off. I might be driving down to London this weekend.

IF they are switched on when the variable limit is NOT operational, I can confirm that they flash at 85mph but not at 70mph. Other cars were passing me at what may have been 80mph and they were not flashing either.

Steve

>14 days. Safe?

Sorry, meant to update this. No NIP yet. My car is a co. car so the NIP may have to go via them but given it is 3 weeks, I think I am safe.

Steve

[Blakewater]

speedyguy said:

littleredrooster said:

gruffalo said:

Trouble I have with this section is that the speed limit is often reduced to 60 or even 50 when the traffic is light and free flowing and the 70 limit should apply.

So that shows the system is working, then. Keeping the traffic free-flowing by adjusting the limits is exactly what it does...

We'll have none of that common sense trying to use optimum traffic flow to smooth everyone's journey rather than stop start traffic with the resultant rear end shunts, (everyones an expert especially on ph ) dontchaknow

[johnao]

littleredrooster said:

Quite the opposite is actually true; maximum capacity on a motorway is reached when the traffic is moving steadily at a speed somewhere between 30 and 40mph surprisingly.

Motorway capacity, or volume of traffic, increases as speeds reduce. Increased capacity doesn't stop as average speeds drop to 30 or 40mph. Capacity continues to increase until all traffic is travelling at 0mph, ie stationary. So, assuming that we do not wish that motorways come to a complete standstill, the optimum motorway capacity is achieved at an average speed of approx. 1mph.

See, that's what will happen when government, the EU, do-gooders, authoritarians and the rest of life's prefects completely take over the world! Drivers, walkers, runners, cyclist, anything that moves, will not be allowed to go at more than 1mph.

[emmaT2014]

johnao said:

littleredrooster said:

Quite the opposite is actually true; maximum capacity on a motorway is reached when the traffic is moving steadily at a speed somewhere between 30 and 40mph surprisingly.

Motorway capacity, or volume of traffic, increases as speeds reduce. Increased capacity doesn't stop as average speeds drop to 30 or 40mph. Capacity continues to increase until all traffic is travelling at 0mph, ie stationary. So, assuming that we do not wish that motorways come to a complete standstill, the optimum motorway capacity is achieved at an average speed of approx. 1mph.

See, that's what will happen when government, the EU, do-gooders, authoritarians and the rest of life's prefects completely take over the world! Drivers, walkers, runners, cyclist, anything that moves, will not be allowed to go at more than 1mph.

You have explained the principle reasonably well but hve then it to a ridiculous level. Traffic headways reduce as speeds reduce and this principle is used to increase capacity, the lowered speed however is taken to a speed that maintains reasonable movement of the traffic. 1mph is not reasonable but 60, 50, 40 and 30 are reasonable speeds and increase the road capacity by allowing vehicles to drive closer together.
50, 40, 40, 40, 30, 50, 60, NSL is acceptable and much better than NSL, 0, 0, 0, NSL ,0, NSL, lane closed to recover damaged vehicles, 0...0...0...0...0...NSL etc

[speedking31]

Where is the flaw in my logic?

Allow 2 s between the rear of the car in front and the front of your vehicle. Length of vehicle = 4.5 m. Maths shows that as speed increases so does the throughput of vehicles per lane. There is no peak at 30/40 mph.




The only way the flow increases is if cars travel closer than 2 s apart at slower speeds.

[Collectingbrass]

speedking31 said:

Where is the flaw in my logic?

Your logic is fine, but your assumptions are too far from the real world for your model to be relevant. You assume every vehicle is the same, driven the same and does not need to change lanes to pass a slower vehicle to point out just three of many. In the real world HGVs are 3 - 4 times the length of your car and limited to 60mph.

If maths is your thing knock yourself out here: http://en.wikipedia.org/wiki/Traffic_flow

Sorry to be a bit spikey about this, but I had to sit through 12 weeks of the most fking boring lectures given by an arse of a professor. And there are no hotties on a Civil Engineering degree course.

[robinessex]

Wandering of topic, re HS2. If you want the maximum train/passenger density, the optimum train speed is circa 40mph !!!! Screws up the governments case for it somewhat !!

[Pit Pony]

Greg66 said:

An alternative view.

Edited by Greg66 on Thursday 29th January 13:35

I was travelling to Hemel from Miseryside for 6 months last year. 226 miles door to door. If you look, only about half of the signs have a camera behind.

Given that mostly I was travelling at 20 mph when the signs read 40 or 50, it wasn't an issue, but occasionally if the traffic was light(er), I'd be bimbling along at 65, only to find the car in front, testing his brakes down to 45 even when the sign showed 60, and ironically there was no actual camera in place.