The OS MasterMap Highways Network with Average Speed product contains detailed average speed information which is calculated using over 135 000 vehicles with inbuilt trackers and GPS loggers and mixed-use vehicle fleet telematic data. The main type of vehicle is cars, but LGVs and HGVs are also used
to calculate the average speed. The data is polled every 1 to 10 seconds and then attached to the Ordnance Survey road network.
The data is then analysed and checked against current and previous polls to ensure the data is captured against the correct OS MasterMap Road Link feature. The average speed data is provided with bi-directionality, meaning two speed values are provided on single-carriageway roads. These speeds are named in the product data as an “A” speed and a “B” speed in km/h. The speed will be given on the road link for the direction of travel. The A side represents the direction from node A to B and is in the direction of digitisation of the road link while the B side is from node B to A and is against the direction of digitisation.
When a link is one-way the speed will always be provided only in the A column attributes.
Within any given month of data collection, there will be 99% coverage of average speed information for Motorways, A Roads and B roads and over 50% coverage of C class roads. For road links or time periods where there is no speed data available over the 12 months, these road links are infilled using neighbouring link information to ensure 100% coverage of data. This data is released annually and built against one version of the Ordnance Survey network; therefore, the complete link matching is for this version only.