Trunk A-road
A477 traffic and collisions
The A477 is a trunk A-road of 28.5 miles, from Carmarthenshire to Pembrokeshire. This page covers its traffic at 7 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 132m vehicle miles
- Average daily traffic 12,693 vehicles a day, both directions
- Busiest section 17,309 At A4075
- HGV share 4.6% of vehicle miles
- Traffic since 2019 +17.9% same count points
- Collisions, 2021 to 2025 124 21.1 per 100m vehicle miles
How busy is the A477?
On an average day in 2025, 12,693 vehicles passed each point on the A477, counting both directions. The busiest section is At A4075 (Pembrokeshire), with 17,309 a day; the quietest listed is A478 to A4075, with 9,874.
Busiest sections, 2025
At A4075 carries 1.4 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| At A4075 Pembrokeshire · 1.6 mi · HGVs 5.0% | 17,309 |
| A4076 to A4139 London Road Pembrokeshire · 5.7 mi · HGVs 2.9% | 16,440 |
| A4075 to A4139 Ferry Lane Pembrokeshire · 2.7 mi · HGVs 4.6% | 14,718 |
| A40 to A478 Carmarthenshire, Pembrokeshire · 12.6 mi · HGVs 5.4% | 11,153 |
| A478 to A4075 Pembrokeshire · 5.8 mi · HGVs 5.6% | 9,874 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Carmarthenshire to Pembrokeshire · 28.5 miles
A477 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 | A40 to A478Carmarthenshire, Pembrokeshire | 11,153 | 30 |
| 2 | A478 to A4075Pembrokeshire | 9,874 | 18 |
| 3 | At A4075Pembrokeshire | 17,309 | 11 |
| 4 | A4075 to A4139 Ferry LanePembrokeshire | 14,718 | 24 |
| 5 | A4139 Ferry Lane to A4139 London RdPembrokeshire | 28,118 | 4 |
| 6 | A4076 to A4139 London RoadPembrokeshire | 16,440 | 36 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A477 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.
A477 traffic by vehicle type
Cars and taxis make up 76.0% of the vehicle miles on the A477. HGVs account for 4.6%.
Vehicle mix, 2025
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
HGV share of traffic
| Year | HGV share |
|---|---|
| 2000 | 6.7% |
| 2001 | 6.6% |
| 2002 | 6.7% |
| 2003 | 6.6% |
| 2004 | 6.2% |
| 2005 | 6.3% |
| 2006 | 6.8% |
| 2007 | 7.5% |
| 2008 | 6.9% |
| 2009 | 6.4% |
| 2010 | 6.7% |
| 2011 | 6.5% |
| 2012 | 6.5% |
| 2013 | 6.6% |
| 2014 | 6.0% |
| 2015 | 6.5% |
| 2016 | 6.5% |
| 2017 | 6.6% |
| 2018 | 6.3% |
| 2019 | 5.8% |
| 2020 | 6.9% |
| 2021 | 6.8% |
| 2022 | 5.0% |
| 2023 | 4.8% |
| 2024 | 4.7% |
| 2025 | 4.6% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A477 traffic trend
Traffic on the A477 came to 132 million vehicle miles in 2025. At the count points present in both years, it is up 17.9% on 2019, before the pandemic, and up 36.6% on 2015.
Vehicle miles a year
Like for like, traffic is up 80.0% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 76m |
| 2001 | 79m |
| 2002 | 83m |
| 2003 | 87m |
| 2004 | 87m |
| 2005 | 90m |
| 2006 | 92m |
| 2007 | 94m |
| 2008 | 96m |
| 2009 | 98m |
| 2010 | 92m |
| 2011 | 93m |
| 2012 | 93m |
| 2013 | 93m |
| 2014 | 96m |
| 2015 | 96m |
| 2016 | 99m |
| 2017 | 100m |
| 2018 | 105m |
| 2019 | 112m |
| 2020 | 80m |
| 2021 | 92m |
| 2022 | 118m |
| 2023 | 121m |
| 2024 | 126m |
| 2025 | 132m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 7,411 |
| 2001 | 7,663 |
| 2002 | 8,072 |
| 2003 | 8,495 |
| 2004 | 8,465 |
| 2005 | 8,762 |
| 2006 | 8,965 |
| 2007 | 9,101 |
| 2008 | 9,348 |
| 2009 | 9,504 |
| 2010 | 8,968 |
| 2011 | 9,046 |
| 2012 | 9,007 |
| 2013 | 9,028 |
| 2014 | 9,316 |
| 2015 | 9,277 |
| 2016 | 9,596 |
| 2017 | 9,723 |
| 2018 | 10,137 |
| 2019 | 10,768 |
| 2020 | 7,730 |
| 2021 | 8,824 |
| 2022 | 11,313 |
| 2023 | 11,670 |
| 2024 | 12,073 |
| 2025 | 12,693 |
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. In 2025, 1 of the 7 count points were counted; DfT estimated the rest from earlier counts and local trends.
A477 collisions
Police recorded 124 collisions with the A477 as the first road from 2021 to 2025, 46 of them fatal or serious, including 4 fatal. That is 21.1 per 100 million vehicle miles, lower than the 31.5 for all A-roads in Great Britain. On average there were 0.9 a year for each mile of road.
Reported collisions by year
Up 89.5% from 2021 to 2025.
| Year | Slight | Fatal or serious |
|---|---|---|
| 2021 | 13 | 6 |
| 2022 | 14 | 7 |
| 2023 | 13 | 7 |
| 2024 | 13 | 15 |
| 2025 | 24 | 12 |
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 |
|---|---|
| A4075 to A4139 Ferry Lane Pembrokeshire · 24 collisions | 38.7 |
| A4076 to A4139 London Road Pembrokeshire · 36 collisions | 24.8 |
| At A4075 Pembrokeshire · 11 collisions | 24.3 |
| A478 to A4075 Pembrokeshire · 18 collisions | 18.8 |
| A40 to A478 Carmarthenshire, Pembrokeshire · 30 collisions | 12.7 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 3 collisions were recorded at junctions where the A477 was the second road; they are not in the figures above. Fatal or serious uses DfT’s adjusted serious figures. 99.2% of the collisions could be placed on a section. How we count collisions
Council areas on the A477
In route order. Each is the highway authority DfT files the count points under.
- Carmarthenshire
- Pembrokeshire
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 | 124 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.