The Department for Transport counts traffic on the M1 at 97 separate points. Once slip roads, spurs and other roads are taken out, and the stretches split across a local-authority boundary are put back together, 42 stretches of M1 mainline have a 2025 figure. They are listed below, busiest first.

The busiest stretch carries more than twice the traffic of the quietest

J42 to J43 carries 159,683 vehicles a day. J2 to J4 carries 66,698. The average across the measured M1 is 119,883. Two drivers can each say they use the M1 every day and be describing roads that differ by a factor of more than two.

Stretch	All vehicles a day	Cars & taxis	Lorries	Miles
J42 to J43	159,683	118,207	12,997	1.5
J7 to J8	158,937	107,921	18,418	1.0
J8 to J9	157,786	107,404	19,287	4.4
J21 to J21A	157,403	109,186	20,291	3.0
J6A to J7	157,142	108,621	18,607	2.5
J31 to J32	155,303	103,705	20,707	2.0
J41 to J42	152,398	110,195	12,984	1.4
J10 to J11†	152,346	107,851	18,555	3.4
J40 to J41†	142,615	101,583	12,582	2.7
J25 to J26†	139,549	94,354	18,029	2.8
J11A to J12	137,679	97,484	17,508	2.5
J34 to J35	136,926	99,592	11,622	3.0
J28 to J29	136,489	85,797	21,096	6.8
J24A to J25†	133,023	86,973	18,098	4.3
J23A to J24	131,396	85,282	19,133	1.9
J39 to J40	130,896	94,020	11,894	2.6
J26 to J27	129,501	86,352	17,174	5.5
J35 to J35A†	127,194	89,615	12,446	1.5
J15 to J15A	123,822	80,752	20,301	2.7
J30 to J31†	122,208	77,956	18,862	5.6
J15A to J16	121,280	79,026	20,315	3.9
J16 to J17	120,092	76,379	22,231	8.6
J14 to J15†	113,762	76,070	17,495	12.2
J44 to J45	112,119	80,126	10,510	1.3
J18 to J19†	110,877	70,672	19,440	3.3
J22 to J23	110,322	74,099	15,038	4.6
J45 to J46	110,133	79,743	9,009	2.7
J36 to J37	107,026	72,580	11,018	4.0
J23 to J23A	106,784	69,625	14,944	4.2
J17 to J18	106,351	67,311	19,518	2.0
J5 to J6	103,178	79,305	4,230	2.5
J35A to J36	101,953	70,691	10,232	1.6
J21A to J22	101,454	70,108	14,392	5.6
J37 to J38	100,622	70,077	10,464	4.3
J38 to J39†	97,475	66,425	10,340	3.5
J20 to J21	90,647	61,001	14,372	10.7
J19 to J20	88,994	58,847	12,322	3.5
J47 to J48	85,104	60,073	8,355	1.6
J46 to J47	83,466	59,899	8,088	2.4
J43 to J44	79,481	55,766	9,514	1.4
J6 to J6A	75,008	59,555	2,568	0.7
J2 to J4	66,698	50,298	3,464	4.2

Source: Department for Transport road traffic statistics, annual average daily flow for 2025. Figures are vehicles per day, averaged across the year, counted at the points the Department measures. Stretches marked † combine two adjacent count points that report the same measurement either side of a local-authority boundary; the distance is the sum of the two. Ten fragments could not be matched to a partner and are left out rather than guessed at.

What these numbers do not tell you

Annual average daily flow counts how many vehicles use a stretch. It does not measure how slowly they travel. A wide four-lane stretch can carry 150,000 vehicles a day and keep moving, while a narrower one carries far fewer and crawls. Busiest is not the same as worst, and this page does not claim it is. For what is happening on the M1 right now, see the latest M1 traffic news.

Where lorries use the M1 most →  ·  All M1 traffic statistics