TfL has a network of over 130 roadside message signs, which provide drivers with information about local traffic disruptions. The signs are set by TfL's London Streets Traffic Control Centre.
The Live Roadside Message Signs XML feed comes direct from TfL's traffic control centre system and contains the location and live message on every sign currently displaying information in London.
The feed contains a date and time stamp which should be used to check that the information is up-to-date and be displayed when publishing the information.
Some ideas...
The information could be combined with TfL's Traffic Camera and Live Traffic Disruptions data feeds to provide a complete picture of traffic along a route or in an area