Trunk A-road
A33 traffic and collisions
The A33 is a trunk A-road of 36.6 miles, from Reading to Southampton. This page covers its traffic at 31 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 306m vehicle miles
- Average daily traffic 22,884 vehicles a day, both directions
- Busiest section 69,132 M271 to A3024
- HGV share 3.4% of vehicle miles
- Traffic since 2019 −3.1% same count points
- Collisions, 2021 to 2025 411 28.4 per 100m vehicle miles
How busy is the A33?
On an average day in 2025, 22,884 vehicles passed each point on the A33, counting both directions. The busiest section is M271 to A3024 (Southampton), with 69,132 a day; the quietest listed is A34 to A30, with 5,581.
Busiest sections, 2025
M271 to A3024 carries 3.0 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| M271 to A3024 Southampton · 1.2 mi · HGVs 6.8% | 69,132 |
| M4 to Mereoak Lane/Basingstoke Road roundabout Reading, Wokingham · 0.5 mi · HGVs 3.0% | 52,005 |
| A35 to West Quay Rd Southampton · 1.8 mi · HGVs 2.8% | 49,004 |
| A33 split to M4 Reading · 2.5 mi · HGVs 1.8% | 40,326 |
| A27 to A35 Southampton · 0.8 mi · HGVs 1.1% | 38,648 |
| A339 to Long Lane roundabout Hampshire · 1.9 mi · HGVs 2.8% | 33,598 |
| Mereoak Lane/Basingstoke Road roundabout to B3349 Wokingham, Hampshire · 3.9 mi · HGVs 4.3% | 32,374 |
| B3349 to Long Lane, Basingstoke Hampshire · 7.0 mi · HGVs 3.8% | 20,340 |
| B3039 to Southern Rd Southampton · 0.6 mi · HGVs 3.9% | 17,594 |
| A33 Threefield Lane/Marsh Lane to A3024 Southampton · 0.5 mi · HGVs 2.4% | 16,532 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Reading to Southampton · 36.6 miles
A33 traffic and collisions by section
24 sections between junctions, in route order. Each is the average of its DfT count points, weighted by length. 5 short link roads and spurs (0.9 miles) count in the road’s totals but are not listed.
Show all 24 sections Tap a column heading to sort
| # | |||
|---|---|---|---|
| 1 | A329 to A33 splitReading | 12,710 | 3 |
| 2 | A33 split to A33 Rose Kiln LaneReading | 28,245 | 11 |
| 3 | A33 split to M4Reading | 40,326 | 45 |
| 4 | M4 to Mereoak Lane/Basingstoke Road roundaboutReading, Wokingham | 52,005 | fewer than 3 |
| 5 | Mereoak Lane/Basingstoke Road roundabout to B3349Wokingham, Hampshire | 32,374 | 19 |
| 6 | B3349 to Long Lane, BasingstokeHampshire | 20,340 | 53 |
| 7 | A339 to Long Lane roundaboutHampshire | 33,598 | 19 |
| 8 | A34 to A30Hampshire | 5,581 | 22 |
| 9 | A33 to M3Hampshire | 8,424 | 7 |
| 10 | M3 to A27Southampton | 32,523 | fewer than 3 |
| 11 | A27 to A35Southampton | 38,648 | 33 |
| 12 | At A35Southampton | 17,901 | 13 |
| 13 | A35 to A3035Southampton | 27,474 | 7 |
| 14 | A3035 to A3024Southampton | 16,200 | 62 |
| 15 | A3024 roundabout to A3024/A33 KingswaySouthampton | 22,780 | 5 |
| 16 | A33 Threefield Lane/Marsh Lane to A3024Southampton | 16,532 | 14 |
| 17 | A33 Evans St to A33 Terminus TerraceSouthampton | 6,205 | 3 |
| 18 | Queens Terrace to Bernard StSouthampton | 10,837 | 5 |
| 19 | Town Quay to Terminus TerraceSouthampton | 24,101 | 4 |
| 20 | A33 split to B3039Southampton | 18,813 | 4 |
| 21 | B3039 to Southern RdSouthampton | 17,594 | 9 |
| 22 | Southern Rd to Mountbatten WaySouthampton | 24,386 | 3 |
| 23 | A35 to West Quay RdSouthampton | 49,004 | 35 |
| 24 | M271 to A3024Southampton | 69,132 | 14 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A33 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.
A33 traffic by vehicle type
Cars and taxis make up 80.8% of the vehicle miles on the A33. HGVs account for 3.4%, rising to 6.8% on M271 to A3024.
Vehicle mix, 2025
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
HGV share of traffic
| Year | HGV share |
|---|---|
| 2000 | 4.2% |
| 2001 | 4.1% |
| 2002 | 3.7% |
| 2003 | 4.0% |
| 2004 | 4.1% |
| 2005 | 4.0% |
| 2006 | 3.6% |
| 2007 | 3.8% |
| 2008 | 3.7% |
| 2009 | 3.4% |
| 2010 | 3.8% |
| 2011 | 3.1% |
| 2012 | 3.1% |
| 2013 | 3.3% |
| 2014 | 3.2% |
| 2015 | 3.7% |
| 2016 | 3.7% |
| 2017 | 4.0% |
| 2018 | 4.3% |
| 2019 | 4.1% |
| 2020 | 4.7% |
| 2021 | 4.5% |
| 2022 | 4.3% |
| 2023 | 3.7% |
| 2024 | 3.6% |
| 2025 | 3.4% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A33 traffic trend
Traffic on the A33 came to 306 million vehicle miles in 2025. At the count points present in both years, it is down 3.1% on 2019, before the pandemic, and down 3.9% on 2015.
Vehicle miles a year
Like for like, traffic is down 3.3% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 290m |
| 2001 | 309m |
| 2002 | 308m |
| 2003 | 298m |
| 2004 | 303m |
| 2005 | 241m |
| 2006 | 238m |
| 2007 | 232m |
| 2008 | 227m |
| 2009 | 221m |
| 2010 | 216m |
| 2011 | 225m |
| 2012 | 224m |
| 2013 | 222m |
| 2014 | 227m |
| 2015 | 240m |
| 2016 | 243m |
| 2017 | 264m |
| 2018 | 318m |
| 2019 | 310m |
| 2020 | 230m |
| 2021 | 259m |
| 2022 | 285m |
| 2023 | 297m |
| 2024 | 300m |
| 2025 | 306m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 23,264 |
| 2001 | 24,749 |
| 2002 | 24,661 |
| 2003 | 23,896 |
| 2004 | 24,243 |
| 2005 | 20,864 |
| 2006 | 20,596 |
| 2007 | 20,014 |
| 2008 | 19,632 |
| 2009 | 19,100 |
| 2010 | 18,631 |
| 2011 | 19,421 |
| 2012 | 19,374 |
| 2013 | 19,148 |
| 2014 | 19,606 |
| 2015 | 20,834 |
| 2016 | 21,147 |
| 2017 | 22,063 |
| 2018 | 24,031 |
| 2019 | 23,426 |
| 2020 | 17,346 |
| 2021 | 19,578 |
| 2022 | 21,504 |
| 2023 | 22,375 |
| 2024 | 22,671 |
| 2025 | 22,884 |
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, 9 of the 31 count points were counted; DfT estimated the rest from earlier counts and local trends.
A33 collisions
Police recorded 411 collisions with the A33 as the first road from 2021 to 2025, 88 of them fatal or serious, including 9 fatal. That is 28.4 per 100 million vehicle miles, close to the 31.5 for all A-roads in Great Britain. On average there were 2.3 a year for each mile of road.
Reported collisions by year
Up 17.8% from 2021 to 2025.
| Year | Slight | Fatal or serious |
|---|---|---|
| 2021 | 57 | 16 |
| 2022 | 77 | 11 |
| 2023 | 58 | 15 |
| 2024 | 71 | 20 |
| 2025 | 60 | 26 |
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 |
|---|---|
| A33 Threefield Lane/Marsh Lane to A3024 Southampton · 14 collisions | 111.1 |
| A3035 to A3024 Southampton · 62 collisions | 98.4 |
| A339 to Long Lane roundabout Hampshire · 19 collisions | 81.6 |
| A27 to A35 Southampton · 33 collisions | 61.5 |
| A34 to A30 Hampshire · 22 collisions | 26.6 |
| A33 split to M4 Reading · 45 collisions | 23.9 |
| A35 to West Quay Rd Southampton · 35 collisions | 22.5 |
| B3349 to Long Lane, Basingstoke Hampshire · 53 collisions | 22.1 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 66 collisions were recorded at junctions where the A33 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 A33
In route order. Each is the highway authority DfT files the count points under.
- Reading
- Wokingham
- Hampshire
- Southampton
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 | 31 count points in 2025 | 15 September 2026 |
| Reported collisions | Road safety open data (STATS19) Department for Transport Derived statistics UK Motoring | 2021 to 2025 | 411 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.