Trunk A-road
A4042 traffic and collisions
The A4042 is a trunk A-road of 19.5 miles, from Newport to Monmouthshire. This page covers its traffic at 10 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 180m vehicle miles
- Average daily traffic 25,310 vehicles a day, both directions
- Busiest section 46,118 A4051 to A472
- HGV share 2.8% of vehicle miles
- Traffic since 2019 +5.1% same count points
- Collisions, 2021 to 2025 117 13.7 per 100m vehicle miles
How busy is the A4042?
On an average day in 2025, 25,310 vehicles passed each point on the A4042, counting both directions. The busiest section is A4051 to A472 (Torfaen), with 46,118 a day; the quietest listed is A472 to A465/A40 intersection, with 12,924.
Busiest sections, 2025
A4051 to A472 carries 1.8 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| A4051 to A472 Torfaen · 1.3 mi · HGVs 1.8% | 46,118 |
| slip to M4 to A4042 split Newport, Torfaen · 1.4 mi · HGVs 2.4% | 42,088 |
| A4042 split to A4051 Torfaen · 4.5 mi · HGVs 2.5% | 35,366 |
| slip to M4 Newport · 0.7 mi · HGVs 1.6% | 35,330 |
| A48 Newport · 0.7 mi · HGVs 2.1% | 22,076 |
| A472 Pontymoel to A472 Berthon Rd Torfaen · 2.6 mi · HGVs 2.8% | 20,782 |
| A4042 to A48 Newport · 0.9 mi · HGVs 2.7% | 18,982 |
| A472 to A465/A40 intersection Monmouthshire · 7.1 mi · HGVs 3.7% | 12,924 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Newport to Monmouthshire · 19.5 miles
A4042 traffic and collisions by section
8 sections between junctions, in route order. Each is the average of its DfT count points, weighted by length. 1 short link roads and spurs (0.3 miles) count in the road’s totals but are not listed.
Sections Tap a column heading to sort
| # | |||
|---|---|---|---|
| 1 | A4042 to A48Newport | 18,982 | 11 |
| 2 | A48Newport | 22,076 | 6 |
| 3 | slip to M4Newport | 35,330 | 0 |
| 4 | slip to M4 to A4042 splitNewport, Torfaen | 42,088 | 12 |
| 5 | A4042 split to A4051Torfaen | 35,366 | 33 |
| 6 | A4051 to A472Torfaen | 46,118 | 12 |
| 7 | A472 Pontymoel to A472 Berthon RdTorfaen | 20,782 | 13 |
| 8 | A472 to A465/A40 intersectionMonmouthshire | 12,924 | 27 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A4042 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.
A4042 traffic by vehicle type
Cars and taxis make up 80.7% of the vehicle miles on the A4042. HGVs account for 2.8%.
Vehicle mix, 2025
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
HGV share of traffic
| Year | HGV share |
|---|---|
| 2000 | 5.0% |
| 2001 | 4.7% |
| 2002 | 4.6% |
| 2003 | 4.5% |
| 2004 | 4.6% |
| 2005 | 4.4% |
| 2006 | 4.2% |
| 2007 | 4.1% |
| 2008 | 3.8% |
| 2009 | 3.5% |
| 2010 | 3.6% |
| 2011 | 3.6% |
| 2012 | 3.9% |
| 2013 | 3.9% |
| 2014 | 3.8% |
| 2015 | 3.5% |
| 2016 | 3.4% |
| 2017 | 3.3% |
| 2018 | 3.4% |
| 2019 | 3.4% |
| 2020 | 3.9% |
| 2021 | 3.7% |
| 2022 | 3.6% |
| 2023 | 3.2% |
| 2024 | 3.2% |
| 2025 | 2.8% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A4042 traffic trend
Traffic on the A4042 came to 180 million vehicle miles in 2025. At the count points present in both years, it is up 5.1% on 2019, before the pandemic, and up 7.3% on 2015.
Vehicle miles a year
Like for like, traffic is up 18.9% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 157m |
| 2001 | 168m |
| 2002 | 147m |
| 2003 | 155m |
| 2004 | 160m |
| 2005 | 153m |
| 2006 | 171m |
| 2007 | 159m |
| 2008 | 172m |
| 2009 | 174m |
| 2010 | 167m |
| 2011 | 167m |
| 2012 | 161m |
| 2013 | 158m |
| 2014 | 167m |
| 2015 | 168m |
| 2016 | 174m |
| 2017 | 174m |
| 2018 | 184m |
| 2019 | 176m |
| 2020 | 126m |
| 2021 | 154m |
| 2022 | 169m |
| 2023 | 173m |
| 2024 | 175m |
| 2025 | 180m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 19,825 |
| 2001 | 21,208 |
| 2002 | 21,831 |
| 2003 | 22,918 |
| 2004 | 23,726 |
| 2005 | 21,619 |
| 2006 | 24,127 |
| 2007 | 22,456 |
| 2008 | 24,306 |
| 2009 | 24,559 |
| 2010 | 23,996 |
| 2011 | 23,921 |
| 2012 | 23,054 |
| 2013 | 22,611 |
| 2014 | 23,904 |
| 2015 | 24,097 |
| 2016 | 25,012 |
| 2017 | 25,017 |
| 2018 | 25,144 |
| 2019 | 24,404 |
| 2020 | 17,719 |
| 2021 | 21,612 |
| 2022 | 23,773 |
| 2023 | 24,357 |
| 2024 | 24,544 |
| 2025 | 25,310 |
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, 2 of the 10 count points were counted; DfT estimated the rest from earlier counts and local trends.
A4042 collisions
Police recorded 117 collisions with the A4042 as the first road from 2021 to 2025, 54 of them fatal or serious, including 3 fatal. That is 13.7 per 100 million vehicle miles, lower than the 31.5 for all A-roads in Great Britain. On average there were 1.2 a year for each mile of road.
Reported collisions by year
Down 17.4% from 2021 to 2025.
| Year | Slight | Fatal or serious |
|---|---|---|
| 2021 | 11 | 12 |
| 2022 | 12 | 9 |
| 2023 | 14 | 17 |
| 2024 | 15 | 8 |
| 2025 | 11 | 8 |
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 |
|---|---|
| A4042 to A48 Newport · 11 collisions | 36.4 |
| A472 to A465/A40 intersection Monmouthshire · 27 collisions | 16.5 |
| A472 Pontymoel to A472 Berthon Rd Torfaen · 13 collisions | 13.7 |
| A4042 split to A4051 Torfaen · 33 collisions | 12.6 |
| A4051 to A472 Torfaen · 12 collisions | 12.0 |
| slip to M4 to A4042 split Newport, Torfaen · 12 collisions | 11.5 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 15 collisions were recorded at junctions where the A4042 was the second road; they are not in the figures above. Fatal or serious uses DfT’s adjusted serious figures. 97.4% of the collisions could be placed on a section. How we count collisions
Council areas on the A4042
In route order. Each is the highway authority DfT files the count points under.
- Newport
- Torfaen
- Monmouthshire
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 | 10 count points in 2025 | 15 September 2026 |
| Reported collisions | Road safety open data (STATS19) Department for Transport Derived statistics UK Motoring | 2021 to 2025 | 117 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.