On Wed, 11 May 2005 07:53:02 +0100, "Vernon"
wrote:

When LBC Travel News talk of travel information derived from "Satellite
Data", what sort of satellite help are they getting? I am aware of GPS for
navigation, but I can't see how that could help with determining the levels
of realtime traffic problems.

Just curious, but does anyone here know?


Knowing them (& the "radio travel news" world) as I do, Yes...I can
tell you.

1: Trafficmaster sensor readings - the blue poles by the side of the
road. www.trafficmaster.net

2: A system run by ITIS called TAG, although I'm not sure whether
they've started using this. Rough system diagram at
http://www.itisholdings.com/ourtech.asp

3: Highways agency "RTT" system - Induction loops in the road surface.
Google it, there's a "non professional" version online somewhere.

All of these, combined with your other information sources can build
up a good picture of what's happening.

HTH

Nik
www.nikthevoice.com