A-road
A4155 traffic and collisions
The A4155 is an A-road of 19.8 miles, from Buckinghamshire to Reading. This page covers its traffic at 12 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 76m vehicle miles
- Average daily traffic 10,552 vehicles a day, both directions
- Busiest section 24,644 A4 to A329
- HGV share 1.9% of vehicle miles
- Traffic since 2019 −8.8% same count points
- Collisions, 2021 to 2025 115 31.1 per 100m vehicle miles
How busy is the A4155?
On an average day in 2025, 10,552 vehicles passed each point on the A4155, counting both directions. The busiest section is A4 to A329 (Reading), with 24,644 a day; the quietest listed is Pound Lane, Marlow to A4130, with 5,328.
Busiest sections, 2025
A4 to A329 carries 2.3 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| A4 to A329 Reading · 0.7 mi · HGVs 2.0% | 24,644 |
| A4094 to A404 Buckinghamshire · 2.4 mi · HGVs 2.4% | 18,153 |
| A404 to B482 Buckinghamshire · 1.1 mi · HGVs 2.3% | 15,707 |
| A4130 to Mill Lane Oxfordshire · 0.8 mi · HGVs 2.1% | 12,508 |
| B478 to A4074 Oxfordshire, Reading · 2.3 mi · HGVs 1.6% | 10,116 |
| B482 to Pound Lane Buckinghamshire · 0.8 mi · HGVs 1.4% | 9,545 |
| Mill Lane, Henley to B478 Oxfordshire · 4.3 mi · HGVs 1.8% | 9,247 |
| Pound Lane, Marlow to A4130 Buckinghamshire, Oxfordshire · 6.8 mi · HGVs 1.0% | 5,328 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Buckinghamshire to Reading · 19.8 miles
A4155 traffic and collisions by section
10 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 | A4155 Cores End Road to A4094Buckinghamshire | 10,000 | fewer than 3 |
| 2 | A4094 to A404Buckinghamshire | 18,153 | 13 |
| 3 | A404 to B482Buckinghamshire | 15,707 | 10 |
| 4 | B482 to Pound LaneBuckinghamshire | 9,545 | 6 |
| 5 | Pound Lane, Marlow to A4130Buckinghamshire, Oxfordshire | 5,328 | 10 |
| 6 | A4130 to Mill LaneOxfordshire | 12,508 | 7 |
| 7 | Mill Lane, Henley to B478Oxfordshire | 9,247 | 9 |
| 8 | B478 to A4074Oxfordshire, Reading | 10,116 | 24 |
| 9 | A4074 to A329NReading | 29,833 | 18 |
| 10 | A4 to A329Reading | 24,644 | 17 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A4155 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.
A4155 traffic by vehicle type
Cars and taxis make up 82.8% of the vehicle miles on the A4155. HGVs account for 1.9%.
Vehicle mix, 2025
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
HGV share of traffic
| Year | HGV share |
|---|---|
| 2000 | 2.5% |
| 2001 | 2.6% |
| 2002 | 2.7% |
| 2003 | 2.7% |
| 2004 | 2.8% |
| 2005 | 2.7% |
| 2006 | 2.7% |
| 2007 | 2.6% |
| 2008 | 2.3% |
| 2009 | 2.1% |
| 2010 | 2.2% |
| 2011 | 2.2% |
| 2012 | 2.3% |
| 2013 | 2.3% |
| 2014 | 2.3% |
| 2015 | 2.2% |
| 2016 | 2.2% |
| 2017 | 2.2% |
| 2018 | 1.9% |
| 2019 | 1.8% |
| 2020 | 2.2% |
| 2021 | 2.3% |
| 2022 | 2.3% |
| 2023 | 2.2% |
| 2024 | 2.1% |
| 2025 | 1.9% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A4155 traffic trend
Traffic on the A4155 came to 76.3 million vehicle miles in 2025. At the count points present in both years, it is down 8.8% on 2019, before the pandemic, and down 10.6% on 2015.
Vehicle miles a year
Like for like, traffic is down 22.2% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 97m |
| 2001 | 91m |
| 2002 | 93m |
| 2003 | 92m |
| 2004 | 93m |
| 2005 | 93m |
| 2006 | 90m |
| 2007 | 89m |
| 2008 | 89m |
| 2009 | 85m |
| 2010 | 85m |
| 2011 | 85m |
| 2012 | 83m |
| 2013 | 82m |
| 2014 | 84m |
| 2015 | 85m |
| 2016 | 86m |
| 2017 | 86m |
| 2018 | 85m |
| 2019 | 84m |
| 2020 | 64m |
| 2021 | 69m |
| 2022 | 73m |
| 2023 | 75m |
| 2024 | 77m |
| 2025 | 76m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 13,513 |
| 2001 | 12,706 |
| 2002 | 12,886 |
| 2003 | 12,816 |
| 2004 | 12,894 |
| 2005 | 12,902 |
| 2006 | 12,533 |
| 2007 | 12,415 |
| 2008 | 12,360 |
| 2009 | 11,859 |
| 2010 | 11,785 |
| 2011 | 11,874 |
| 2012 | 11,498 |
| 2013 | 11,340 |
| 2014 | 11,623 |
| 2015 | 11,757 |
| 2016 | 11,943 |
| 2017 | 11,895 |
| 2018 | 11,721 |
| 2019 | 11,572 |
| 2020 | 8,782 |
| 2021 | 9,477 |
| 2022 | 10,138 |
| 2023 | 10,380 |
| 2024 | 10,600 |
| 2025 | 10,552 |
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 12 count points were counted; DfT estimated the rest from earlier counts and local trends.
A4155 collisions
Police recorded 115 collisions with the A4155 as the first road from 2021 to 2025, 28 of them fatal or serious. That is 31.1 per 100 million vehicle miles, close to 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
Up 8.0% from 2021 to 2025.
| Year | Collisions |
|---|---|
| 2021 | 25 |
| 2022 | 32 |
| 2023 | 18 |
| 2024 | 13 |
| 2025 | 27 |
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 |
|---|---|
| B478 to A4074 Oxfordshire, Reading · 24 collisions | 59.3 |
| A4 to A329 Reading · 17 collisions | 56.1 |
| A404 to B482 Buckinghamshire · 10 collisions | 32.1 |
| A4094 to A404 Buckinghamshire · 13 collisions | 17.0 |
| Pound Lane, Marlow to A4130 Buckinghamshire, Oxfordshire · 10 collisions | 14.8 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 16 collisions were recorded at junctions where the A4155 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 A4155
In route order. Each is the highway authority DfT files the count points under.
- Buckinghamshire
- Oxfordshire
- Reading
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 | 12 count points in 2025 | 15 September 2026 |
| Reported collisions | Road safety open data (STATS19) Department for Transport Derived statistics UK Motoring | 2021 to 2025 | 115 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.