A-road
A4055 traffic and collisions
The A4055 is an A-road of 8.3 miles, from Cardiff to The Vale of Glamorgan. This page covers its traffic at 7 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 45m vehicle miles
- Average daily traffic 14,694 vehicles a day, both directions
- Busiest section 36,336 A4232 to A4160
- HGV share 1.3% of vehicle miles
- Traffic since 2019 +6.5% same count points
- Collisions, 2021 to 2025 63 30.3 per 100m vehicle miles
How busy is the A4055?
On an average day in 2025, 14,694 vehicles passed each point on the A4055, counting both directions. The busiest section is A4232 to A4160 (Cardiff, The Vale of Glamorgan), with 36,336 a day; the quietest listed is Park Ave/Harbour Rd/St Nicholas Road triangle to Barry Island Pleasure Park, with 4,867.
Busiest sections, 2025
A4232 to A4160 carries 2.5 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| A4232 to A4160 Cardiff, The Vale of Glamorgan · 0.7 mi · HGVs 1.5% | 36,336 |
| Cross-Common Rd to A4231 The Vale of Glamorgan · 1.2 mi · HGVs 1.3% | 18,625 |
| B4267 Penlan Rd to Cross-Common Road The Vale of Glamorgan · 1.6 mi · HGVs 1.9% | 18,023 |
| A4231 to Park Ave/Harbour Rd/St Nicholas Road triangle The Vale of Glamorgan · 3.6 mi · HGVs 0.5% | 8,789 |
| Park Ave/Harbour Rd/St Nicholas Road triangle to Barry Island Pleasure Park The Vale of Glamorgan · 0.8 mi · HGVs 0.8% | 4,867 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Cardiff to The Vale of Glamorgan · 8.3 miles
A4055 traffic and collisions by section
6 sections between junctions, in route order. Each is the average of its DfT count points, weighted by length.
Sections Tap a column heading to sort
| # | |||
|---|---|---|---|
| 1 | A4232 to A4160Cardiff, The Vale of Glamorgan | 36,336 | 6 |
| 2 | A4160 Cogan Hill to B4267 Penlan RdThe Vale of Glamorgan | 24,508 | 6 |
| 3 | B4267 Penlan Rd to Cross-Common RoadThe Vale of Glamorgan | 18,023 | 11 |
| 4 | Cross-Common Rd to A4231The Vale of Glamorgan | 18,625 | 7 |
| 5 | A4231 to Park Ave/Harbour Rd/St Nicholas Road triangleThe Vale of Glamorgan | 8,789 | 30 |
| 6 | Park Ave/Harbour Rd/St Nicholas Road triangle to Barry Island Pleasure ParkThe Vale of Glamorgan | 4,867 | fewer than 3 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A4055 as the first road, placed on the nearest section by their recorded position; rates (per 100 million vehicle miles) are shown for sections of half a mile or more with 10 or more.
A4055 traffic by vehicle type
Cars and taxis make up 84.7% of the vehicle miles on the A4055. HGVs account for 1.3%.
Vehicle mix, 2025
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
HGV share of traffic
| Year | HGV share |
|---|---|
| 2000 | 2.2% |
| 2001 | 2.0% |
| 2002 | 1.9% |
| 2003 | 1.9% |
| 2004 | 1.9% |
| 2005 | 1.9% |
| 2006 | 2.0% |
| 2007 | 2.6% |
| 2008 | 2.5% |
| 2009 | 2.4% |
| 2010 | 2.3% |
| 2011 | 2.3% |
| 2012 | 2.3% |
| 2013 | 2.4% |
| 2014 | 2.3% |
| 2015 | 1.4% |
| 2016 | 1.4% |
| 2017 | 1.5% |
| 2018 | 1.6% |
| 2019 | 1.6% |
| 2020 | 1.8% |
| 2021 | 1.6% |
| 2022 | 1.6% |
| 2023 | 1.3% |
| 2024 | 1.3% |
| 2025 | 1.3% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A4055 traffic trend
Traffic on the A4055 came to 44.5 million vehicle miles in 2025. At the count points present in both years, it is up 6.5% on 2019, before the pandemic, and up 0.8% on 2015.
Vehicle miles a year
Like for like, traffic is down 1.5% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 45m |
| 2001 | 42m |
| 2002 | 42m |
| 2003 | 43m |
| 2004 | 44m |
| 2005 | 44m |
| 2006 | 43m |
| 2007 | 41m |
| 2008 | 41m |
| 2009 | 39m |
| 2010 | 39m |
| 2011 | 39m |
| 2012 | 40m |
| 2013 | 40m |
| 2014 | 40m |
| 2015 | 41m |
| 2016 | 41m |
| 2017 | 40m |
| 2018 | 42m |
| 2019 | 42m |
| 2020 | 32m |
| 2021 | 38m |
| 2022 | 41m |
| 2023 | 42m |
| 2024 | 43m |
| 2025 | 45m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 16,060 |
| 2001 | 14,772 |
| 2002 | 15,090 |
| 2003 | 15,336 |
| 2004 | 15,745 |
| 2005 | 15,616 |
| 2006 | 15,306 |
| 2007 | 14,641 |
| 2008 | 14,495 |
| 2009 | 13,860 |
| 2010 | 13,916 |
| 2011 | 13,973 |
| 2012 | 14,108 |
| 2013 | 14,082 |
| 2014 | 14,321 |
| 2015 | 14,407 |
| 2016 | 14,730 |
| 2017 | 14,203 |
| 2018 | 14,596 |
| 2019 | 14,437 |
| 2020 | 11,111 |
| 2021 | 13,095 |
| 2022 | 14,031 |
| 2023 | 14,636 |
| 2024 | 14,917 |
| 2025 | 14,694 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
The chart counts the whole road as it was each year, so new or renumbered stretches move it. The percentage changes compare only count points present in both years (56.6% of today’s road for 2019). In 2025, 0 of the 7 count points were counted; DfT estimated the rest from earlier counts and local trends.
A4055 collisions
Police recorded 63 collisions with the A4055 as the first road from 2021 to 2025, 15 of them fatal or serious. That is 30.3 per 100 million vehicle miles, close to the 31.5 for all A-roads in Great Britain. On average there were 1.5 a year for each mile of road.
Reported collisions by year
About the same in 2025 as in 2021.
| Year | Collisions |
|---|---|
| 2021 | 13 |
| 2022 | 8 |
| 2023 | 14 |
| 2024 | 15 |
| 2025 | 13 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
Sections with the highest collision rates
Per 100 million vehicle miles, 2021 to 2025. Sections of half a mile or more with 10 or more collisions.
| Section | Per 100m vehicle miles |
|---|---|
| A4231 to Park Ave/Harbour Rd/St Nicholas Road triangle The Vale of Glamorgan · 30 collisions | 259.8 |
| B4267 Penlan Rd to Cross-Common Road The Vale of Glamorgan · 11 collisions | 21.6 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 8 collisions were recorded at junctions where the A4055 was the second road; they are not in the figures above. Fatal or serious uses DfT’s adjusted serious figures. How we count collisions
Council areas on the A4055
In route order. Each is the highway authority DfT files the count points under.
- Cardiff
- The Vale of Glamorgan
Data sources and methodology
| Figures | Source | Period | Records | Updated |
|---|---|---|---|---|
| Traffic counts and vehicle mix | Road traffic statistics (AADF by count point) Department for Transport Derived statistics UK Motoring | 2000 to 2025 | 7 count points in 2025 | 15 September 2026 |
| Reported collisions | Road safety open data (STATS19) Department for Transport Derived statistics UK Motoring | 2021 to 2025 | 63 reported collisions | 15 September 2026 |
- Annual average daily flow (AADF) is the average number of vehicles passing a point on a typical day of the year, both directions combined.
- Vehicle miles are AADF multiplied by link length and 365, summed over every count point link on the road.
- Sections join count point links between junctions, using the link lines in DfT’s major road database.
- STATS19 covers personal injury collisions reported to the police. Damage-only collisions are not included, and not every injury collision is reported.
- Serious and slight figures are DfT’s adjusted estimates, which allow for police forces moving to injury-based reporting.
- Counts of one or two collisions below Great Britain level are shown as “fewer than 3”.
Contains public sector information licensed under the Open Government Licence v3.0.