Local authority Portsmouth

Region: South East
Count points: 115
Time period: 2000 to 2022
Source: Road traffic statistics

0.76 billion vehicle miles were travelled on roads in Portsmouth in 2022.

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 2011 and 2019. Following a sharp decline in 2020, traffic levels in 2021 and 2022 increased, but 2022 levels still remain lower than the 2016 levels. Therefore, to say traffic has fallen since 2016 would misconstrue as the overall decrease is entirely due to the decline in traffic levels observed during the pandemic.


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Data disclaimer

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.

Data Description Records Download
Count points Count points in Portsmouth details. 115 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. 30 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. 1,518 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. 2,570 JSON | CSV
Raw counts Vehicle counts recorded at this count point. 12,636 JSON | CSV