A sweeping bend on a British A road at dusk with a motorcyclist mid-corner.

Original analysis · STATS19 and DfT traffic counts

The roads that are actually most dangerous

Name: Motorcyclist and cyclist casualty rates per billion vehicle miles by road, Great Britain 2021 to 2025
Creator: Department for Transport
License: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

Every danger ranking you have read counts casualties. Counting rewards long, busy roads. We measured the rate instead.

Last updated: 31 August 2026

1,710

Roads ranked

4 of 20

Top count roads that are also top rate roads

0.86x

The A38, against the national average

2,170

GB rate, motorcyclist KSI per billion miles

Why every "most dangerous road" list is wrong

Britain's road danger rankings, including the one we published on this site, count casualties. The A38 comes top because 183 motorcyclists were killed or seriously injured on it between 2021 and 2025. What that mostly measures is that the A38 is 296 miles long and busy. Riders cover about 99 million miles a year on it.

Divide the casualties by the miles ridden and the picture inverts. The A38 records 1,858 motorcyclist KSI casualties per billion vehicle miles, against a national average on major roads of 2,170. It is a below average road. It ranks 1,116th of the 1,710 roads we can measure.

Of the twenty roads that top the casualty count, twelve are below the national average per mile ridden. Only four of them are also in the top twenty by rate.

What we did

The Department for Transport publishes two things separately. STATS19 records every road casualty reported to the police, including which road it happened on. The AADF traffic counts record how much traffic uses each stretch of road, broken out by vehicle type, including a column for two wheeled motor vehicles and one for pedal cycles.

Put them together and you get a rate: casualties per billion vehicle miles ridden on that road. Nobody publishes this for motorcyclists, so we have.

99.9% of motorcyclist casualties on major numbered roads matched to traffic data for the same road and year.

The roads with the highest motorcyclist casualty rates

Click a column heading to sort. The table scrolls sideways on smaller screens.

Motorcyclist casualties killed or seriously injured per billion vehicle miles, Great Britain major roads, 2021 to 2025. Roads with at least 30 KSI casualties, ranked on the lower bound of the interval.

1	A29	42	0.006	7,446	5,367 to 10,065	3.43x	54
2	A57	87	0.017	5,229	4,188 to 6,450	2.41x	20
3	A259	181	0.039	4,691	4,032 to 5,426	2.16x	2
4	A85	34	0.006	5,684	3,936 to 7,942	2.62x	69
5	A62	30	0.006	5,267	3,554 to 7,519	2.43x	87
6	A272	59	0.014	4,356	3,316 to 5,619	2.01x	34
7	A44	70	0.017	4,077	3,178 to 5,151	1.88x	26
8	A18	36	0.009	4,198	2,940 to 5,812	1.93x	66
9	A32	46	0.012	3,984	2,917 to 5,314	1.84x	45
10	A35	101	0.029	3,522	2,869 to 4,280	1.62x	15
11	A6	159	0.049	3,278	2,788 to 3,829	1.51x	4
12	A26	40	0.010	3,885	2,775 to 5,290	1.79x	59
13	A16	39	0.010	3,876	2,756 to 5,298	1.79x	60
14	A25	44	0.012	3,788	2,752 to 5,085	1.75x	50
15	A149	40	0.011	3,789	2,707 to 5,159	1.75x	58
16	A215	44	0.012	3,653	2,654 to 4,903	1.68x	48
17	A339	30	0.008	3,930	2,652 to 5,610	1.81x	90
18	A124	30	0.008	3,915	2,641 to 5,589	1.80x	86
19	A58	41	0.011	3,672	2,635 to 4,981	1.69x	55
20	A270	30	0.008	3,839	2,590 to 5,480	1.77x	85
21	A458	32	0.009	3,728	2,550 to 5,263	1.72x	76
22	A22	48	0.014	3,442	2,538 to 4,564	1.59x	43
23	A487	41	0.012	3,519	2,526 to 4,775	1.62x	56
24	A23	148	0.052	2,864	2,422 to 3,365	1.32x	8
25	A228	30	0.008	3,582	2,417 to 5,113	1.65x	89
26	A21	68	0.023	2,911	2,261 to 3,690	1.34x	27
27	A350	42	0.013	3,131	2,256 to 4,232	1.44x	53
28	A505	35	0.011	3,186	2,219 to 4,431	1.47x	67
29	A165	32	0.010	3,233	2,212 to 4,565	1.49x	77
30	A61	62	0.022	2,797	2,145 to 3,586	1.29x	31
31	A28	33	0.011	3,110	2,141 to 4,368	1.43x	75
32	A104	36	0.012	3,049	2,136 to 4,222	1.41x	63
33	A370	32	0.010	3,113	2,129 to 4,394	1.43x	81
34	A329	34	0.011	3,002	2,079 to 4,195	1.38x	68
35	A361	57	0.021	2,720	2,060 to 3,524	1.25x	35
36	A27	130	0.054	2,419	2,021 to 2,872	1.11x	10
37	A414	46	0.017	2,745	2,010 to 3,662	1.26x	46
38	A59	50	0.018	2,704	2,007 to 3,564	1.25x	42
39	A112	31	0.011	2,927	1,989 to 4,155	1.35x	83
40	A36	36	0.013	2,838	1,988 to 3,929	1.31x	65

Every road here carries at least 30 killed or seriously injured casualties, so these are not small number flukes, and the interval shown is an exact Poisson 95% interval on the casualty count. Roads are ranked on the bottom of that interval rather than the headline figure, so a road cannot reach the top on a lucky run of bad years.

The same twenty roads, counted and rated

Click a column heading to sort. The table scrolls sideways on smaller screens.

The twenty roads with the most motorcyclist KSI casualties, shown with their rate per mile ridden and their position in the rate ranking.

1	A38	183	1,858	0.86x	1,116
2	A259	181	4,691	2.16x	366
3	A40	162	1,432	0.66x	1,247
4	A6	159	3,278	1.51x	631
5	A4	156	1,889	0.87x	1,104
6	A5	151	2,337	1.08x	944
7	A2	150	1,820	0.84x	1,131
8	A23	148	2,864	1.32x	755
9	A13	131	1,595	0.74x	1,191
10	A27	130	2,419	1.11x	909
11	A3	128	1,316	0.61x	1,288
12	A406	111	1,531	0.71x	1,212
13	A41	110	1,935	0.89x	1,085
14	A30	105	1,840	0.85x	1,123
15	A35	101	3,522	1.62x	574
16	A1	98	1,136	0.52x	1,338
17	A10	91	1,992	0.92x	1,061
18	A24	89	2,342	1.08x	942
19	A12	88	1,117	0.51x	1,342
20	A57	87	5,229	2.41x	308
21	A47	82	2,299	1.06x	953
22	A205	76	2,455	1.13x	896
23	A20	73	1,987	0.92x	1,063
24	A82	71	1,342	0.62x	1,277
25	A46	70	1,703	0.78x	1,159
26	A44	70	4,077	1.88x	467
27	A21	68	2,911	1.34x	742
28	M25	67	737	0.34x	1,418
29	A39	65	2,283	1.05x	958
30	A34	64	1,445	0.67x	1,241
31	A61	62	2,797	1.29x	773
32	A404	61	2,411	1.11x	913
33	A11	59	2,380	1.10x	925
34	A272	59	4,356	2.01x	427
35	A361	57	2,720	1.25x	795
36	A503	54	2,588	1.19x	847
37	A52	54	2,411	1.11x	914
38	A470	53	2,118	0.98x	1,012
39	A49	52	2,394	1.10x	920
40	A217	51	1,888	0.87x	1,105

This is the same data seen the other way round. The A3, the A12 and the A1 all appear on danger lists every year. Per mile ridden they run at about half the national average.

The roads riders travel for

This is the part that matters to anyone reading this on a bike.

The A57 over Snake Pass carries 5,229 motorcyclist KSI casualties per billion miles ridden, 2.41 times the national average, from 87 killed or seriously injured in five years. It is 308th of 1,710 by rate and 20th by count, which is unusual: most roads are high on one list or the other, not both.

The A686 over Hartside runs at 12,109 per billion miles, 5.58 times the national average, though on 24 casualties rather than 87, so the interval is wide and it sits outside our main table.

Not every famous road is dangerous. The A537 Cat and Fiddle, which had a reputation bad enough to get average speed cameras, now records 6 KSI casualties in five years and runs below the national average per mile.

Cyclists

Click a column heading to sort. The table scrolls sideways on smaller screens.

Pedal cyclist casualties killed or seriously injured per billion cycle miles, Great Britain major roads, 2021 to 2025. Roads with at least 30 KSI casualties.

A23	102	0.042	2,438	1,988 to 2,960	1.01x
A5	60	0.023	2,590	1,976 to 3,334	1.07x
A10	105	0.040	2,625	2,147 to 3,178	1.08x
A3220	40	0.015	2,705	1,932 to 3,683	1.12x
A315	88	0.032	2,724	2,185 to 3,356	1.12x
A219	55	0.020	2,774	2,090 to 3,611	1.14x
A105	42	0.015	2,778	2,002 to 3,755	1.15x
A217	48	0.017	2,840	2,094 to 3,766	1.17x
A202	72	0.025	2,862	2,239 to 3,604	1.18x
A41	44	0.015	2,879	2,092 to 3,865	1.19x
A6	97	0.033	2,920	2,368 to 3,562	1.20x
A107	37	0.012	3,042	2,142 to 4,193	1.26x
A27	40	0.013	3,045	2,175 to 4,146	1.26x
A35	33	0.010	3,195	2,199 to 4,487	1.32x
A24	95	0.028	3,363	2,721 to 4,112	1.39x
A58	32	0.009	3,389	2,318 to 4,784	1.40x
A2	71	0.020	3,534	2,760 to 4,458	1.46x
A61	50	0.014	3,684	2,734 to 4,857	1.52x
A308	85	0.022	3,849	3,075 to 4,759	1.59x
A404	40	0.010	3,950	2,822 to 5,379	1.63x
A205	84	0.021	3,997	3,188 to 4,949	1.65x
A46	33	0.008	4,320	2,974 to 6,067	1.78x
A214	31	0.007	4,340	2,949 to 6,160	1.79x
A11	103	0.022	4,708	3,843 to 5,710	1.94x
A21	41	0.008	4,983	3,576 to 6,760	2.06x

The national figure for cyclists on major roads is 2,423 KSI casualties per billion cycle miles. The worst roads for cyclists are a different set from the worst roads for motorcyclists, and they cluster around London and the commuter routes into it.

What this does not say

A rate is not a verdict on a road. Three things could each move these numbers and we cannot separate them: how the road is built, how fast people ride on it, and who rides there.

The traffic figures are annual average daily flows. They tell us how much riding happens on a road across a year, not what the traffic was on the day of any particular collision.

Casualties are assigned to the first road recorded for the collision, so a crash at a junction between two roads counts against one of them.

Only motorways and A roads can be rated. The Department for Transport publishes minor road count points as a rotating statistical sample without link lengths, so no mileage can be derived for B, C and unclassified roads. They are excluded here, and a lot of riding happens on them.

Police data undercounts injured riders, and undercounts injured cyclists more. Every count here is a floor.

Method

Numerator: DfT STATS19 casualty and collision files for 2021 to 2025, casualties assigned to the first road of the collision. Motorcyclist means casualty_type 2, 3, 4, 5, 23 or 97, which covers riders and passengers of any engine size. Cyclist means casualty_type 1.

Denominator: DfT AADF traffic counts for the same five years. Vehicle miles for a road in a year is the sum, over every count point on that road, of the annual average daily flow multiplied by the link length in miles multiplied by 365. The two wheeled motor vehicles column is used for motorcyclists and the pedal cycles column for cyclists.

As a check on the denominator, the same method applied to all motor vehicles gives 223 billion vehicle miles on Britain's major roads in 2025, which is close to two thirds of the national all roads total, the split the Department for Transport reports. Summed link lengths also reproduce real road lengths: 296 miles for the A38, 118 for the A57, 274 for the A9.

Intervals are exact Poisson 95% intervals on the casualty count.

Data and citation

Published under the Open Government Licence v3.0. Contains public sector information licensed from the Department for Transport.

Cite as: Bikers.co.uk (2026), Motorcyclist and cyclist casualty rates per billion vehicle miles by road, Great Britain 2021 to 2025. Derived from DfT STATS19 and DfT AADF traffic counts.

Download the data (JSON)

Frequently asked questions

What is the most dangerous road in Britain for motorcyclists?

It depends what you measure. By number of casualties it is the A38, with 183 motorcyclists killed or seriously injured between 2021 and 2025. Measured against how far people actually ride, the A38 is below average and the highest rate among roads with at least 30 casualties is the A29 in Sussex, at 7,446 KSI casualties per billion vehicle miles against a national average of 2,170.

Is the A38 really Britain's most dangerous road?

It has the most motorcyclist casualties, because it is 296 miles long and carries about 99 million motorcycle miles a year. Per mile ridden it runs at 0.86 times the national average and ranks 1,116th of 1,710 roads.

Is Snake Pass dangerous?

Per mile ridden, yes. The A57 records 5,229 motorcyclist KSI casualties per billion vehicle miles, 2.41 times the national average, from 87 killed or seriously injured over five years.

How can a road with more deaths be safer?

Because a long, busy road gives more opportunities for something to go wrong. Counting casualties measures exposure as much as danger. Dividing by miles ridden removes that, and the ranking changes: only four of the top twenty roads by count are also in the top twenty by rate.

Where does this data come from?

The Department for Transport, in two parts. STATS19 for the casualties and the AADF traffic counts for the traffic. Both are open data under the Open Government Licence.