Local authority Cardiff
1.64 billion vehicle miles were travelled on roads in Cardiff in 2020.
Whilst historically significant, the long term trends can be misleading in most cases due to the extraordinary circumstances observed as a result of the coronavirus pandemic. Vehicle miles travelled in Great Britain have had year-on-year growth in each year between 2010 and 2019. However, the sharp decrease in 2020 has resulted in traffic estimates that are lower than the 2010 levels. Therefore, to say traffic has fallen over the last decade would misconstrue, as the overall decrease is entirely due to the decline in traffic levels observed in the 2020 estimates.
Traffic estimates for the period since 2010 have been revised to take into account the minor road benchmarking exercise. Further details available on GOV.UK: Road traffic statistics: minor road benchmarking
Traffic figures at the regional and national level are robust, and are reported as National Statistics. However, DfT’s traffic estimates for individual road links and small areas are less robust, as they are not always based on up-to-date counts made at these locations. Where other more up-to-date sources of traffic data are available (e.g. from local highways authorities), this may provide a more accurate estimate of traffic at these locations.
It is the responsibility of the user to decide which data are most appropriate for their purpose, and if DfT road link level traffic estimates are used, to make a note of the limitations in any published material.
Quality flags in data downloads
DfT’s road link level traffic estimates are calculated using a variety of methods, with some methods likely to produce more accurate estimates than others.
The data tables available to download here contain a column - estimation_method – showing the method used to estimate traffic for each location and year. Figures having an estimation method of “Counted” are likely to be more accurate than those marked as “Estimated”, and the latter should be used with caution.
|Count points||Count points in Cardiff details.||199||JSON | CSV|
|Traffic||Traffic is calculated by multiplying AADF by the corresponding length of road and by the number of days in the given year.||28||JSON | CSV|
|Average annual daily flow||Number of vehicles that travel past the count point (in both directions) on an average day of the year.||2,120||JSON | CSV|
|Average annual daily flow by direction||Number of vehicles that travel past the count point on an average day of the year, by direction of travel.||4,151||JSON | CSV|
|Raw counts||Vehicle counts recorded at this count point.||28,044||JSON | CSV|