cool want one

[The Natural Philosopher]

Mine (TomTom Go) appears to take readings from other cars with the TomTom satnavs and work out...

1/. If anyone has reported a mobile speed camera 2/. If the road is heavily congested (hasn't got quite around to road is closed). 3/. If the road is mainly slow even when obviously not congested.

I suspect a massive database back at TomTom HQ with every bit of road between two junctions having a 'normal speed' and 'current speed' set on it. It is clearly dynamic, because as congestion occurs it suggests alternative routes, and they actually work

In today's 'Drive by road furniture' it allows me not to worry about that, and actually concentrate on the road.

[alan_m]

My "Ford" Sat Nav also has real time traffic information to re-route for congestion and on long journeys (100+ miles) will do so 30 to 60 minutes before reaching a potential slow down.

[Bob Eager]

Yes, it was several years ago that I got my first "Ford" satnav. I used it almost immediately for an early day visit to Croydon (my son had an industrial tribunal where he basically demolished the expensive barrister the other side had hired, and the judge congratulated him). Ther was a major hold-up on the way, and it worked nicely round it. We hadn't even realised there was one until we reached the far end of the diversion it gave us, and my son looked back.

It failed to get the other major one on the way to a funeral. A tree had gone across the road. I was third in the queue, and it could easily have fallen on me. Can't really blame the satnav for that one.

[Rod Speed]

alan_m [e-mail]> wrote

But what matters is the source of the congestion data.

The google system of using the movement of cars as observed by mobile phone base data is by far the most useful and reliable.

Particularly for quickly detecting the effect of a car crash on congestion.