DfT > AADFs > Data Availability

Data Available On This Site

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Introduction

The annual average daily flow of traffic available on this web site is for all major roads i.e. motorways and A roads and excludes minor roads and excludes minor roads (see also Data Definitions). The roads are broken up into a series of links with each link comprising a stretch of major road between 2 consecutive junctions with other major roads. A link may also start/end at a local authority boundary or an urban/rural area boundary. A traffic count takes place on each link of the major road network and is used to estimate the annual average daily traffic flows. These data and the associated road network information described below can be viewed and downloaded from this web site. The data are available for each year from 1999 to 2007. 

Road network

Provides information about the roads network (see also Data Definitions ) as follows:

• Unique reference for the region (RegNo) and the region name (Region).
• Unique reference for the local transport authority (LACode) and the authority name (TransportAuthority).
• Unique reference for the road link (CountPoint) that links the network to the traffic count information.
• Date the road was opened (dOpened).
• Date the road was closed (dClosed) which is given where a road was open in 1999 and has subsequently been closed.
• Road classification number (Road).
• Type of road (Category).
• Link length in kilometres (Length).
• Grid reference for the traffic count point (CPEast and CPNorth).

Estimated Annual Average Daily Flows (AADFs)

There is an AADF for each link in the major road network for each year the link is open. How National Traffic Estimates Are Made describes how the AADFs are estimated. Data are provided for the years 1999 to 2007 and the information (see also Data Definitions ) is:

• Unique reference for the road link (CountPoint) that links the AADFs to the road network.
• Year that a manual count last took place (Year) - note that where this is blank, estimates are based on the manual counts of adjacent traffic count points.
• Estimated AADFs for 11 vehicle types, a sub-total for heavy goods vehicles and a total for all motor vehicles.

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