D-Rider wrote:HowardQ wrote:
There was a rumour going around a while ago that they could get GPS info from sat navs to measure individual vehicle speeds, but it never got confirmed.
Depends what you mean by "They".
Most currently have no means of getting this info out of the car at present though TomTom HD systems report back so that traffic info can be gleaned in order to identify average speeds and thus congestion (amongst other things)
My understanding is that this is aggregated info and not individually identified (and as most systems are portable between vehicles are relatively anonymous anyway)
HowardQ wrote:
The more recent technology is more worrying, I have even seen readouts for roads in my local village for average speeds between two points and in many cases I can't see any evidence of sensors, in other cases there are the ones you mention and other boxed areas.
I don't know how they do it but some of these they even manage to specify all types of vehicle in the info.
One means of determining average traffic speed is from cell phones. Phone network companies aggregate the data and can provide historical traffic information. This is sold for many purposes - including route planning.
I'm not saying this is definitely the case for the the roads you mention but it is a common technique that is used that requires no specific additional infrastructure.
Capability will increase with V2X development (V2X being the global amalgamation of V2V or vehicle to vehicle communication and V2I or vehicle to infrastructure)
The requirement to equip all cars with e-call systems will result in every new vehicle being equipped with GPS and a cellular data link - primarily for automatic calling of the emergency services - but once all that is in the car it's there for other uses too.
The main thing that worries me on the last one is how they identify the types of vehicle.
I have seen data examples from 2002 with average speeds for cars, medium goods vehicles and HGVs, which were taken from from the old wire accross the road to a box systems. Can't give a technical explanation but the wire obviously had the option to indicate the vehicle weight so they probably assumed the tree classes of vehicle totally based on the weight on the wire. They then just produced average speed data for all vehicle types. For this data sample taken in 2002, there were no bikes measured.
Interestingly, the vehicle type which most consistently broke the 30 limit were HGVs, almost all of which were 40 to 45mph.
The highest speed logged in this sample was by a car at 49mph.
The test was mid to late afternoon, so school leaving time.
this was ten years ago. These wire data samples are occasionally still used but only in simple cases.
The most recent examples I have seen were much more comprehensive and had average speeds for all different bits of all the roads I checked.
These were roads within a few 100 metres of my house where I have never seen any wired data collectors and on a walk around I could see nothing to indicate how the data had been collected, (other than a few sensor areas in the road, but not enough).
The data was supplied direct to Local Authority type body, (not a Council), from the Transport Ministry.
This was not highly clasified stuff from MI5 or something just standard stuff sent out on a CD following a request.
I can only think of things like sat navs and mobile phones as being possible ways of collecting this, but cannot work out how they get even more accurate vehicle type data.
I did once give somebody a lift to go out and download one of the speed warning signs (simple link via a laptop ), but never saw this data. Could there also be a camera within the unit that gives simple images that they can identify. could it be an ANPR type but they only use it for vehicle type analysis at this time.
Whatever, we are getting much closer to full vehicle data logging whenever the Government feel they need it.
It would only
ever be used to track terrorists obviously, and could
never be used in court, (unless the camera indicated a mobile traffic offence or something).
And finally!
The Government were actually talking about fitting transmitters to bikes as a trial so all speeds could be logged. They backed off late in the day.
