jomukuk wrote:
whynot wrote:
It does seem unbelievable that it is considered necessary for a driver to be told there is spray on a motorway when it is wet. I would consider it pretty obvious, but it does seem these days that unless people are told everything they are unable to work anything out for themselves.
Whilst discussing matrix signs, it amazes me how often they display a reduced speed that bears little or no resemblance to the conditions. There are several places on the M27 where you can see a matrix sign displaying a reduced speed with the next one on showing end and there is nothing happening in between. Do I need to be told to slow to 40mph when I can see clearly a mile further up the road that is clear? Again this does not encourage motorists to take what is displayed seriously.
The speed limits vary to slow traffic down as it approaches congestion.
You may well be able to see one mile, the data systems that HA are monitoring see the entire network.
Just because your single mile is free-flowing does not mean that 20 miles down the road it is the same.
Have a read through this site:
http://www.nrtsco.com/website/home.doPop a few downloads and look at the system existing now...
Unfortunately, many drivers think as you do. specially those on the A1M approaching London, which is why they always get bogged-down in jams....traffic flowing at 40 is better than traffic floating about between 0 and 20.
Quite, If congestion sensitive VSL is working properly then you will rarely, if ever, see any congestion.
(The relationship between highway capacity (Vehicles/hour past a single point) and average speed is an interesting one, and not what many people would think! Question 1). At what average speed does a highway avchieve its maximum capacity? Quston 2) Why does traffic "surge" as maximum capacity is approached

)
Access controll has a part to play too but I am not sure if it is used anywhere in the UK.