Has anyone monitored the accuracy of the live traffic facility on Gmaps? I had an eye on it in the course of recent family travels and was pretty impressed. Over the years I've found the Highways Agency / Traffic England live maps uselessly slow and unreliable. The best facility on the latter site is the Motorway Traffic Flow page, where you can monitor speeds junction by junction on specified m-ways, which does seem accurate and is helpful for long-haul journeys.