A-road
A363 traffic and collisions
The A363 is an A-road of 10.4 miles, from Wiltshire to Bath and North East Somerset. This page covers its traffic at 11 DfT count points since 2000 and the collisions police recorded on it.
- Traffic in 2025 48m vehicle miles
- Average daily traffic 12,758 vehicles a day, both directions
- Busiest section 19,609 A361 to Woodmarsh roundabout
- HGV share 2.5% of vehicle miles
- Traffic since 2019 +4.5% same count points
- Collisions, 2021 to 2025 102 44.8 per 100m vehicle miles
How busy is the A363?
On an average day in 2025, 12,758 vehicles passed each point on the A363, counting both directions. The busiest section is A361 to Woodmarsh roundabout (Wiltshire), with 19,609 a day; the quietest listed is B3108 to B3105, with 8,213.
Busiest sections, 2025
A361 to Woodmarsh roundabout carries 1.5 times the road’s average flow.
| Section | Vehicles a day |
|---|---|
| A361 to Woodmarsh roundabout Wiltshire · 0.8 mi · HGVs 1.1% | 19,609 |
| Woodmarsh roundabout, Trowbridge to A361 Wiltshire · 1.2 mi · HGVs 5.1% | 16,827 |
| A363 Trowbridge Road to B3109 Wiltshire · 0.7 mi · HGVs 1.0% | 13,584 |
| A366 to Westwood Rd Wiltshire · 0.7 mi · HGVs 1.0% | 13,514 |
| B3105 to Bathford Hill Wiltshire, Bath and North East Somerset · 4.1 mi · HGVs 3.4% | 11,278 |
| Westwood Rd, Trowbridge to A363 Junction Rd Wiltshire · 1.6 mi · HGVs 0.7% | 10,502 |
| B3108 to B3105 Wiltshire · 0.6 mi · HGVs 2.0% | 8,213 |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Route
Wiltshire to Bath and North East Somerset · 10.4 miles
A363 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 | Woodmarsh roundabout, Trowbridge to A361Wiltshire | 16,827 | 15 |
| 2 | A361 to Woodmarsh roundaboutWiltshire | 19,609 | 17 |
| 3 | A366 to B3106Wiltshire | 10,751 | 6 |
| 4 | A366 Wingfield Road roundabout to B3106 roundaboutWiltshire | 20,857 | 3 |
| 5 | A366 to Westwood RdWiltshire | 13,514 | 9 |
| 6 | Westwood Rd, Trowbridge to A363 Junction RdWiltshire | 10,502 | 17 |
| 7 | A363 Trowbridge Road to B3109Wiltshire | 13,584 | 11 |
| 8 | B3108 to B3105Wiltshire | 8,213 | 5 |
| 9 | B3105 to Bathford HillWiltshire, Bath and North East Somerset | 11,278 | 19 |
| 10 | Bathford Hill to A4Bath and North East Somerset | 13,947 | 0 |
Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A363 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.
A363 traffic by vehicle type
Cars and taxis make up 78.9% of the vehicle miles on the A363. HGVs account for 2.5%, rising to 5.1% on Woodmarsh roundabout, Trowbridge to A361.
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 | 3.7% |
| 2004 | 3.9% |
| 2005 | 3.5% |
| 2006 | 3.4% |
| 2007 | 3.1% |
| 2008 | 3.1% |
| 2009 | 2.4% |
| 2010 | 2.5% |
| 2011 | 2.5% |
| 2012 | 2.5% |
| 2013 | 2.4% |
| 2014 | 2.4% |
| 2015 | 2.4% |
| 2016 | 2.5% |
| 2017 | 2.7% |
| 2018 | 2.8% |
| 2019 | 2.8% |
| 2020 | 3.2% |
| 2021 | 3.1% |
| 2022 | 2.9% |
| 2023 | 2.8% |
| 2024 | 2.5% |
| 2025 | 2.5% |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
A363 traffic trend
Traffic on the A363 came to 48.4 million vehicle miles in 2025. At the count points present in both years, it is up 4.5% on 2019, before the pandemic, and up 6.8% on 2015.
Vehicle miles a year
Like for like, traffic is up 11.5% on 2000.
| Year | Vehicle miles |
|---|---|
| 2000 | 43m |
| 2001 | 45m |
| 2002 | 44m |
| 2003 | 46m |
| 2004 | 46m |
| 2005 | 46m |
| 2006 | 46m |
| 2007 | 45m |
| 2008 | 44m |
| 2009 | 44m |
| 2010 | 44m |
| 2011 | 44m |
| 2012 | 43m |
| 2013 | 44m |
| 2014 | 45m |
| 2015 | 45m |
| 2016 | 48m |
| 2017 | 47m |
| 2018 | 46m |
| 2019 | 46m |
| 2020 | 36m |
| 2021 | 41m |
| 2022 | 45m |
| 2023 | 45m |
| 2024 | 48m |
| 2025 | 48m |
Source:DfT,UK Motoring analysis 2000 to 2025 Updated
Average daily flow
| Year | Vehicles a day |
|---|---|
| 2000 | 11,443 |
| 2001 | 11,961 |
| 2002 | 11,604 |
| 2003 | 12,002 |
| 2004 | 12,165 |
| 2005 | 12,156 |
| 2006 | 12,132 |
| 2007 | 11,927 |
| 2008 | 11,618 |
| 2009 | 11,643 |
| 2010 | 11,470 |
| 2011 | 11,514 |
| 2012 | 11,284 |
| 2013 | 11,545 |
| 2014 | 11,837 |
| 2015 | 11,951 |
| 2016 | 12,581 |
| 2017 | 12,443 |
| 2018 | 12,176 |
| 2019 | 12,207 |
| 2020 | 9,390 |
| 2021 | 10,886 |
| 2022 | 11,722 |
| 2023 | 11,961 |
| 2024 | 12,629 |
| 2025 | 12,758 |
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, 0 of the 11 count points were counted; DfT estimated the rest from earlier counts and local trends.
A363 collisions
Police recorded 102 collisions with the A363 as the first road from 2021 to 2025, 20 of them fatal or serious. That is 44.8 per 100 million vehicle miles, higher than the 31.5 for all A-roads in Great Britain. On average there were 2.0 a year for each mile of road.
Reported collisions by year
Down 6.3% from 2021 to 2025.
| Year | Collisions |
|---|---|
| 2021 | 16 |
| 2022 | 17 |
| 2023 | 23 |
| 2024 | 31 |
| 2025 | 15 |
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 |
|---|---|
| A363 Trowbridge Road to B3109 Wiltshire · 11 collisions | 66.1 |
| A361 to Woodmarsh roundabout Wiltshire · 17 collisions | 61.3 |
| Westwood Rd, Trowbridge to A363 Junction Rd Wiltshire · 17 collisions | 60.0 |
| Woodmarsh roundabout, Trowbridge to A361 Wiltshire · 15 collisions | 42.3 |
| B3105 to Bathford Hill Wiltshire, Bath and North East Somerset · 19 collisions | 24.7 |
Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated
A further 10 collisions were recorded at junctions where the A363 was the second road; they are not in the figures above. Fatal or serious uses DfT’s adjusted serious figures. 100.0% of the collisions could be placed on a section. How we count collisions
Council areas on the A363
In route order. Each is the highway authority DfT files the count points under.
- Wiltshire
- Bath and North East Somerset
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 | 11 count points in 2025 | 15 September 2026 |
| Reported collisions | Road safety open data (STATS19) Department for Transport Derived statistics UK Motoring | 2021 to 2025 | 102 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.