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Published 22 January 2013

This section provides technical information, notes and guidance and pre-release access relating to Free flow speeds statistics

Technical information

Free flow speed statistics are produced by monitored traffic speeds at about 100 sites using Automatic Traffic Counters (ATC), deliberately located where external factors which might restrict driver behaviour are not present.

Statistics are presented by different road types and by different vehicle types. The term ‘built-up’ is used to describe roads on which a 40 mph or lower limit applies; the term ‘non-built-up’ describes all other roads.

National administrations in England, Scotland and Wales are responsible for setting speed limits on motorways and trunk ‘A’ roads. Local authorities have the power to impose or vary speed limits on principal roads and on all other local roads. Details of speed limits by vehicle for different road categories can be found below.

Further technical information on the Free flow speeds series:

User Feedback

We continuously review the content of these statistics to ensure they are meeting users’ needs. A summary of the feedback we have received from users is available in:

We continue to welcome any feedback on these statistics. Feedback may be given via the contact details provided below:

National statistics

All of the statistics published in this series are National Statistics. Free flow speeds statistics was assessed by the UK Statistics Authority and confirmed as National Statistics in February 2013.

Assessment of statistics on Maritime, Road traffic, Bus, Taxi, Light rail and Disabled parking badges

Pre-release access list

The post holders given access to these statistics up to 24 hours prior to release are available in the Pre-release Access List.