Collection

Road congestion and reliability statistics

This series brings together all documents relating to road congestion and reliability statistics

See all statistics published by DfT

Road congestion on locally managed ‘A’ roads is measured by estimating the average speed achieved by vehicles during the weekday morning peak, from 7am to 10am. Average speeds are presented at national, regional and local highway authority level.

Reliability on Highways Agency’s motorways and ‘A’ roads is measured by the percentage of ‘journeys’ that are ‘on time’, comparing journey times with historical data for individual sections of road. Statistics are presented at a national level and for individual junction to junction road sections.

Statistical releases on both measures in this series are published on a quarterly basis (in February, May, August and November). The statistical datasets supporting the road congestion on locally managed ‘A’ roads publications are updated on a quarterly or annual basis (in November). The datasets supporting the reliability on Highways Agency’s motorways and ‘A’ roads are updated on a monthly basis.

Business Plan Indicator - Reliability of journeys on the Highways Agency’s motorway and A road network

External websites

Highways Agency

Contact us

Road congestion and reliability statistics enquiries

Technical information

This section provides technical information, notes and guidance and pre-release access relating to road congestion and reliability statistics.

These statistics used to monitor road congestion and journey time reliability are compiled from journey time data from in-vehicle Global Positioning Systems (GPS) and flows estimated using automatic traffic counters and the Department’s manual traffic count data. A brief introduction into these statistics, including what they measure, how they are published and how they are used is available below:

An introduction into the Department for Transport’s congestion statistics

A list of all the tables relating to this series, including archived statistics can be accessed using the link below.

Road congestion and reliability statistics table index

Additional technical information relating to the reliability of journeys on the Highways Agency’s network, locally managed ‘A’ roads, public attitudes and research and development are available at the road traffic, speeds and congestion statistics guidance documentation.

National statistics

All of the statistics published in this series are National Statistics. Road congestion and reliability statistics were assessed by the UK Statistics Authority and confirmed as National Statistics in July 2012.

Road reliability and congestion: Assessment report

Letter of confirmation

Raw data available for download

Highways Agency network journey time and flow data for 15-minute time periods

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.

Publications released during 2014

  1. Reliability of journeys on Highways Agency roads: England, Oct to Dec 2013

    • 13 February 2014
    • Statistics - national statistics
  2. Congestion statistics on local ‘A’ roads, England: Oct to Dec 2013

    • 13 February 2014
    • Statistics - national statistics

Publications released during 2013

  1. Reliability of journeys on the Highways Agency's motorway and A road network: November 2012

    • 10 January 2013
    • Statistics - national statistics
  2. Congestion on local authority managed 'A' roads: October to December 2012

    • 14 February 2013
    • Statistics - national statistics
  3. Reliability of journeys on the Highways Agency's motorway and A road network: December 2012

    • 14 February 2013
    • Statistics
  4. Reliability of journeys on the Highways Agency's motorway and A road network: January 2013

    • 14 March 2013
    • Statistics
  5. Reliability of journeys on the Highways Agency's motorway and A road network: February 2013

    • 11 April 2013
    • Statistics - national statistics
  6. Congestion on local authority managed 'A' roads: January to March 2013

    • 9 May 2013
    • Statistics - national statistics
  7. Reliability of journeys on the Highways Agency's motorway and A road network: March 2013

    • 9 May 2013
    • Statistics - national statistics
  8. Reliability of journeys on the Highways Agency's motorway and A road network: April 2013

    • 13 June 2013
    • Statistics - national statistics
  9. Reliability of journeys on Highways Agency’s motorway and ‘A’ road network: April to June 2013

    • 8 August 2013
    • Statistics - national statistics
  10. Congestion on local authority managed 'A' roads: April to June 2013

    • 8 August 2013
    • Statistics - national statistics
  11. Congestion statistics on locally managed ‘A’ roads, England: Jul to Sep 2013

    • 14 November 2013
    • Statistics - national statistics
  12. Reliability of journeys on Highways Agency roads: England, Jul to Sep 2013

    • 14 November 2013
    • Statistics - national statistics

Data tables associated with this series

  1. Highway Agency motorways and A roads: ‘On time’ journeys (CGN01)

    • 13 February 2014
    • Statistical data set
  2. Flow weighted vehicle speeds (CGN02)

    • 13 February 2014
    • Statistical data set
  3. Flow weighted vehicle speeds, by region (CGN09)

    • 8 August 2013
    • Statistical data set

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