OT Google Maps and Live Traffic details?

[Chris J Dixon]

The calculation is capped at legal speeds ;-)

Chris

[Chris J Dixon]

I had an interesting visit to the National Control Centre where the system was explained to us. They combine motorway and Trafficmaster camera data, and speed loops.

They then perform a calculation including historical data for the section of road, anything known about impending delays (such as special events), current measured flows and speed limits.

They were also emphatic that the sophistication of their algorithm gives the predicted time for a car entering the section, not simply the time taken by one that has just left.

Chris

[tony sayer]

Up to a centimetre resolution?. Your taking there of enhanced differential GPS, not just the triangulation timing info a cell phone may have....

[Huge]

OK, 50 centimetres. And only in places where there are enough femtocells; Oxford Street is the canonical example. But I have seen it demonstrated by a cellphone operator; you can tell whether people are inside a shop or standing on the pavement outside.

Obviously, in the countryside or anywhere else the cells are large, the resolution falls dramatically - hundreds of metres (although this is a guess.)

[tony sayer]

Under ideal conditions possibly but seeing the amount of multipath reflections in urban environments I doubt that accuracy is more than a few instances..

Out in the sticks yes Voda manage to do a few hundred metres and to do this thing properly you need three base stations in range which sometimes is a tad difficult;!.

This company offer these services..

About right sometimes more distant;!..

[John Rumm]

In which case you need to former followed by the latter ;-)

[The Other Mike]

It's even less accurate if say an A road is closed due to an incident / accident, all you get from Google is an indication of congestion at junctions or roads some distance away and zero congestion at the point of closure. As an isolated method of route planning, the Google Maps traffic overlay is worse than useless.

Traffic reports on BBC local radio can also be useless wittering on about total s**te for a minute or so before coming to the important bits, at which point the RDS TA flag times out and you are returned to Radio 4

I heard one the other week, a few miles before a point where a choice of an alternative route could have easily been made. It mentioned congestion on the M1 at junction x. Not a problem, we are on the A1. Then a few miles later the carriageway came to a crawl and then a complete stop. Did we hear wrong, no they repeated the incorrect announcement 30 minutes later when we were sat with the engine off in a solid queue of traffic a few miles from A1 junction x. x being identical. Was it two incidents? No the highways agency website, courtesy of a smartphone, showed only one incident, on the A1.

Both times during this traffic announcement this f****it at the local radio station mentioned a football match 100 miles away that was SFA to do with the traffic.

The incident had been ongoing for a good 30 mins or so before were entered the point of no return yet the Highways Agency also didn't put anything relevant on their warning signs preferring instead to mention something like 'M5 junction 31 exit closed next Thursday for 19 minutes at 2am'

[The Natural Philosopher]

>>> I've found it to be fairly accurate in towns - less so as you hit less busy

Cant beat Sally Traffic on R2...

[ARW]

> >

For long distance journeys she is good company:-)

But I also stick the TA on for more local details.

I also have traffic master on the sat nav (that is usually pretty good, sometimes to within 10m of the hold up) and a road atlas that I know how to use.

[Dave Liquorice]

For the few minutes she is on but the rest of the time you have to put up with R2. No TA on the nationals.

I don't normally bother, except if it's "drive time". The quality of the information varies greatly, not only from station to station but by time of day. I've been stuck on the A1 for 4+ hours late evening and has there been a TA? Nope. This was before the evening syndication or taking of one of the nationals as a sustaining service... And even during drive time some stations only report on the places that always clag up and nowhere else. Then of course they assume everyone knows where the junction of Broad St and Evan Place is that is closed due to an incident, they sometimes don't even say which town...

The highways info boards on motorways aren't bad, they do tell you well in advance but they assume that every one knows their junction numbers. "M6 CLOSED AFTER J27" WTF is J27? I know where I'm going, don't know the junction number I'm coming off at but it's in the highish 20's... Why can't they just say "M6 CLOSED AFTER J27 A5209 WIGAN"?

Real Traffic Master or the RDS delivered service? (Mind you I'm not sure where the RDS service gets it's information from, might be TM). Does TM they still have the YQ? That was excellent, accurate up to date information over the major routes of the entire country. Able to see the clag ups well in advance and make routing decisions 100+ miles in advance, M1 clogged N of Nottingham, stay on the the A1. Not in a hurry, M25 still a car park? Stay at home have another cup of coffee.

[Chris J Dixon]

I have often wondered why that is the case.

Roundabouts seem to be the worst - you don't even get a road name which you might be able to search for.

Round here you get Spider Island, Blue Peter Island, Crusader Island...

Chris