Hounslow in west London has been identified as the UK local authority with the greatest potential audience for roadside advertising, according to a new study from promotional products company Pens.com.
The analysis of Department for Transport data found that an average of 232.2 vehicles pass over each km of road in Hounslow every hour, giving the area nearly 50 times more traffic than the least trafficked area in the UK. The Department for Transport publishes road traffic estimates by vehicle type, road type, and local authority.
London boroughs dominate the rankings, accounting for six of the top 10 locations. Hillingdon ranks 2nd, with 225.2 vehicles per hour per km, a figure attributed to its position as home to Heathrow Airport and several major motorways.
Thurrock in Essex ranks 3rd, with 210.7 vehicles per hour per km. Its location near the M25 and Dartford Crossing makes it an important route for commuters and freight transport into London.
Cardiff is the highest ranked location outside England, placing 4th with 201.9 vehicles per hour per km. As the capital of Wales, its roads handle significant commuter traffic and serve as a regional transport hub.
Enfield ranks 5th with 200.4 vehicles per hour per km, followed by Salford in Greater Manchester with 199.6, making it the highest ranked location in northwest England. Kingston upon Thames and Tower Hamlets take 7th and 8th places, with 197.8 and 197.7 respectively. Warrington ranks 9th with 194.5, while Bury completes the top 10 with 193.0.
The full top 10 rankings
| Rank | Local Authority | Region | Vehicles Per Hour Per KM | Daily Vehicles Per KM |
| 1 | Hounslow | London | 232.2 | 5,572.6 |
| 2 | Hillingdon | London | 225.2 | 5,404.0 |
| 3 | Thurrock | East of England | 210.7 | 5,056.0 |
| 4 | Cardiff | Wales | 201.9 | 4,845.2 |
| 5 | Enfield | London | 200.4 | 4,809.0 |
| 6 | Salford | Greater Manchester | 199.6 | 4,791.2 |
| 7 | Kingston upon Thames | London | 197.8 | 4,747.2 |
| 8 | Tower Hamlets | London | 197.7 | 4,745.8 |
| 9 | Warrington | Cheshire | 194.5 | 4,667.9 |
| 10 | Bury | Greater Manchester | 193.0 | 4,633.1 |
The findings show higher traffic volumes around major urban centres, particularly London, with regional differences reflecting population density and economic activity.
Rural areas record lowest traffic volumes
At the opposite end of the rankings, rural areas and island communities recorded substantially lower levels of road traffic. The Isles of Scilly had the lowest traffic density in the UK, with just 4.7 vehicles per hour per km of road.
The study attributes this to the islands’ small resident population and limited road network. Orkney Islands ranked second lowest, with 9.9 vehicles per hour per km, followed by Comhairle nan Eilean Siar, also known as the Western Isles, with 12.4.
The Shetland Islands recorded 15.4 vehicles per hour per km, followed by Powys in Wales with 21.5. As the largest county in Wales by area but with a relatively small population, its extensive rural landscape contributes to its low traffic density.
Ceredigion recorded 23.7 vehicles per hour per km, followed by Argyll and Bute with 25.2. The Scottish Borders and Highland council areas each recorded 27.3, while Pembrokeshire completed the bottom 10 with 30.8 despite being a popular tourist destination during the summer months.
The lowest 10 areas
| Rank | Local Authority | Region | Vehicles Per Hour Per KM | Daily Vehicles Per KM |
| 1 | Isles of Scilly | South West England | 4.7 | 112.2 |
| 2 | Orkney Islands | Scotland | 9.9 | 237.5 |
| 3 | Comhairle nan Eilean Siar | Scotland | 12.4 | 297.3 |
| 4 | Shetland Islands | Scotland | 15.4 | 370.6 |
| 5 | Powys | Wales | 21.5 | 514.9 |
| 6 | Ceredigion | Wales | 23.7 | 568.6 |
| 7 | Argyll & Bute | Scotland | 25.2 | 604.8 |
| 8 | Scottish Borders | Scotland | 27.3 | 655.2 |
| 9 | Highland | Scotland | 27.3 | 655.4 |
| 10 | Pembrokeshire | Wales | 30.8 | 738.4 |
A spokesperson from Pens.com commented on the findings: “This data provides key insights for businesses considering roadside advertising opportunities. The difference in traffic flow between urban and rural areas demonstrates the need for targeted approaches based on location.”
“What stood out to us was Thurrock in Essex ranking above most London boroughs. It shows how logistics hubs and crossing points like the Dartford Crossing can generate enormous traffic volumes that businesses might not expect.”