Department for Transport (DfT) traffic statistics provide estimates of the vehicle miles travelled each year in Great Britain, by:
We release both quarterly and annual estimates.
The finalised Annual Road Traffic Estimates for the period ending December 2017 are due to be published in May 2018. As announced in the last Provisional Road Traffic Estimates publication, we are not publishing provisional traffic estimates for Q4 2017 in February. The decision to only publish final estimates for the year ending December 2017 is as a result of user feedback.
DfT road traffic statistics team are conducting a review of the traffic estimates for Great Britain. The aim of the review is to ensure robust traffic estimates continue to be produced, seeking innovation and greater value for money in their production while protecting user needs. The review is due to be completed in 2016.
Provisional traffic estimates are based on traffic data collected continuously from a national network of around 180 Automatic Traffic Counters (ATC).
Provisional estimates are published quarterly and remain provisional until they have been constrained by the final annual estimates each year.
Final annual road traffic estimates are mainly based on around ten thousand manual counts, which are combined with ATC data and road lengths to produce overall estimates.
Traffic estimates for major roads are based on a census whereas traffic estimates for minor roads are estimated by calculating growth rates from a fixed sample of count points on the minor road network.