A-road

A411 traffic and collisions

The A411 is an A-road of 14.2 miles, from Barnet to Hertfordshire. This page covers its traffic at 18 DfT count points since 2000 and the collisions police recorded on it.

Last updated
Records analysed
18 count points in 2025
Methodology
View methodology
  • Traffic in 2025 95m vehicle miles
  • Average daily traffic 18,393 vehicles a day, both directions
  • Busiest section 33,297 At A4008
  • HGV share 0.9% of vehicle miles
  • Traffic since 2019 −3.1% same count points
  • Collisions, 2021 to 2025 209 45.7 per 100m vehicle miles

How busy is the A411?

On an average day in 2025, 18,393 vehicles passed each point on the A411, counting both directions. The busiest section is At A4008 (Hertfordshire), with 33,297 a day; the quietest listed is A409 to A4140, with 9,141.

Busiest sections, 2025

At A4008 carries 1.8 times the road’s average flow.

Sections of the A411 with the highest average daily flow, 2025
Section Vehicles a day
At A4008 Hertfordshire · 1.1 mi · HGVs 1.0% 33,297
Beechen Grove split to A411 Exchange Rd Hertfordshire · 0.5 mi · HGVs 1.3% 23,888
Courtlands Drive to M25 Hertfordshire · 0.7 mi · HGVs 0.9% 22,732
A1(T) to A5183 Hertfordshire · 2.1 mi · HGVs 0.8% 18,779
A412 to Courtlands Drive Hertfordshire · 1.7 mi · HGVs 0.9% 17,968
A1000 to Quinta Drive Barnet · 1.3 mi · HGVs 0.6% 15,534
A5183 to A41(T) Hertfordshire · 1.0 mi · HGVs 0.7% 14,555
A4140 to A4008 Hertfordshire · 1.7 mi · HGVs 0.6% 13,056
Quinta Drive to A1(T) Barnet · 1.4 mi · HGVs 0.9% 12,358
A409 to A4140 Hertfordshire · 0.8 mi · HGVs 1.1% 9,141

Source:DfT,UK Motoring analysis 2000 to 2025 Updated

Route

Barnet to Hertfordshire · 14.2 miles

Barnet Hertfordshire
Schematic route: each line joins the junctions at the ends of a DfT count point link.

A411 traffic and collisions by section

14 sections between junctions, in route order. Each is the average of its DfT count points, weighted by length. 4 short link roads and spurs (0.8 miles) count in the road’s totals but are not listed.

Sections Tap a column heading to sort
Sections of the A411 in route order, 2025 traffic
#
1A1000 to Quinta DriveBarnet1.315,5340.6%−20.7%3284.2
2Quinta Drive to A1(T)Barnet1.412,3580.9%+10.2%1451.1
3A1(T) to A5183Hertfordshire2.118,7790.8%+17.1%2334.6
4A5183 to A41(T)Hertfordshire1.014,5550.7%+0.6%7
5A41(T) to A409Hertfordshire0.427,1631.1%+5.0%3
6A409 to A4140Hertfordshire0.89,1411.1%−6.4%3
7A4140 to A4008Hertfordshire1.713,0560.6%−6.9%2973.5
8At A4008Hertfordshire0.115,5020.9%+13.4%fewer than 3
9At A4008Hertfordshire1.133,2971.0%−15.9%1928.1
10A4008 to A411 Beechen Grove splitHertfordshire0.233,6791.1%−3.9%4
11Beechen Grove split to A411 Exchange RdHertfordshire0.523,8881.3%−1.9%7
12A411 Exchange Rd to A412Hertfordshire0.423,6400.8%−6.2%10
13A412 to Courtlands DriveHertfordshire1.717,9680.9%−4.7%1833.6
14Courtlands Drive to M25Hertfordshire0.722,7320.9%+1.4%7

Vehicles a day is the average daily flow in 2025. “Since 2019” compares the same count points. Collisions are those with the A411 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.

A411 traffic by vehicle type

Cars and taxis make up 84.2% of the vehicle miles on the A411. HGVs account for 0.9%.

Vehicle mix, 2025

Source:DfT,UK Motoring analysis 2000 to 2025 Updated

HGV share of traffic

HGVs as a share of vehicle miles on the A411, by year
Year HGV share
2000 1.9%
2001 1.8%
2002 2.2%
2003 2.5%
2004 2.3%
2005 2.1%
2006 1.9%
2007 1.9%
2008 2.0%
2009 1.7%
2010 1.8%
2011 1.7%
2012 1.6%
2013 1.6%
2014 1.6%
2015 1.6%
2016 1.6%
2017 1.5%
2018 1.3%
2019 1.3%
2020 1.5%
2021 1.4%
2022 1.3%
2023 1.1%
2024 1.0%
2025 0.9%

Source:DfT,UK Motoring analysis 2000 to 2025 Updated

A411 traffic trend

Traffic on the A411 came to 95.3 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 4.0% on 2015.

Vehicle miles a year

Like for like, traffic is down 4.6% on 2000.

Vehicle miles on the A411 each year, the whole road as it was that year
Year Vehicle miles
2000 93m
2001 92m
2002 93m
2003 92m
2004 94m
2005 94m
2006 97m
2007 95m
2008 94m
2009 95m
2010 92m
2011 96m
2012 98m
2013 96m
2014 98m
2015 97m
2016 98m
2017 97m
2018 98m
2019 98m
2020 77m
2021 85m
2022 91m
2023 92m
2024 95m
2025 95m

Source:DfT,UK Motoring analysis 2000 to 2025 Updated

Average daily flow

Average daily flow along the A411, weighted by link length, by year
Year Vehicles a day
2000 18,798
2001 18,691
2002 18,943
2003 18,639
2004 18,993
2005 19,074
2006 19,597
2007 19,200
2008 18,971
2009 19,309
2010 18,663
2011 18,967
2012 19,262
2013 19,001
2014 19,322
2015 19,171
2016 19,309
2017 19,108
2018 18,945
2019 18,982
2020 14,853
2021 16,376
2022 17,473
2023 17,729
2024 18,300
2025 18,393

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, 5 of the 18 count points were counted; DfT estimated the rest from earlier counts and local trends.

A411 collisions

Police recorded 209 collisions with the A411 as the first road from 2021 to 2025, 43 of them fatal or serious. That is 45.7 per 100 million vehicle miles, higher than the 31.5 for all A-roads in Great Britain. On average there were 2.9 a year for each mile of road.

Reported collisions by year

About the same in 2025 as in 2021.

Police-reported collisions on the A411 by year: fatal or serious, and slight
Year SlightFatal or serious
2021 328
2022 317
2023 3013
2024 417
2025 328

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.

Collisions per 100 million vehicle miles by section of the A411, 2021 to 2025
Section Per 100m vehicle miles
A1000 to Quinta Drive Barnet · 32 collisions 84.2
A4140 to A4008 Hertfordshire · 29 collisions 73.5
Quinta Drive to A1(T) Barnet · 14 collisions 51.1
A1(T) to A5183 Hertfordshire · 23 collisions 34.6
A412 to Courtlands Drive Hertfordshire · 18 collisions 33.6
At A4008 Hertfordshire · 19 collisions 28.1

Source:DfT STATS19,UK Motoring analysis 2021 to 2025 Updated

A further 49 collisions were recorded at junctions where the A411 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 A411

In route order. Each is the highway authority DfT files the count points under.

  • Barnet
  • Hertfordshire

Data sources and methodology

Datasets used on this page
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 18 count points in 2025 15 September 2026
Reported collisions Road safety open data (STATS19) Department for Transport
Derived statistics UK Motoring
2021 to 2025 209 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.