How Busy Is the M40, Junction by Junction?

The Department for Transport measures M40 traffic at 33 count points. Once the duplicate entries are removed, those give one figure for each of the 17 stretches of main line between the M25 end and the M42. The table ranks them from busiest to quietest, using the 2025 figures.

Stretch	All vehicles	Cars & taxis	Lorries	Link length (miles)
J1A to J2	136,403	104,618	8,242	5.0
J2 to J3	133,167	103,737	7,496	2.9
J14 to J15	113,433	85,791	9,678	1.2
J3 to J4	102,154	78,386	6,656	3.7
J5 to J6	100,922	78,570	8,311	1.8
J9 to J10	100,293	73,618	10,708	5.6
J4 to J5	99,611	74,991	6,646	7.6
J16 to M42 J3A	96,672	71,046	8,185	1.6
J6 to J7	95,958	73,654	6,528	5.7
J1 to J1A	94,888	71,109	5,976	1.6
J15 to J16	94,041	68,830	9,748	8.8
J7 to J8	92,005	70,631	6,448	0.9
J11 to J12	89,483	64,260	11,036	5.6
J12 to J13	88,881	65,953	10,226	5.3
J10 to J11	88,618	64,662	8,575	1.1
J13 to J14	88,446	66,101	8,405	1.7
J8 to J9	70,986	49,781	7,735	3.5

Link length is the length the Department for Transport assigns to each count point, not necessarily the full distance between the two junctions.

What the ranking shows

The London end is in a league of its own. The two stretches either side of Beaconsfield carry 136,403 and 133,167 vehicles a day. That is nearly twice the traffic on the quietest stretch, Junctions 8 to 9 on the eastern side of Oxford, at 70,986.

Oxford splits the flow. At Junction 8 the A40 leaves for Oxford and Cheltenham, and at Junction 9 the A34 and A41 join. The stretch in between is the quietest on the road; the stretch after Junction 9 is back above 100,000 as traffic from the A34 joins.

Warwick and Leamington are a second peak. Junctions 14 to 15 carry 113,433 a day, more than any stretch between High Wycombe and Birmingham. Junction 15 is where the A46 crosses for Coventry and Stratford-upon-Avon.

The middle is steady. From Banbury to Leamington, Junctions 10 to 14, the figures sit within about 1,000 vehicles of each other, between 88,446 and 89,483.

Duplicates and what we left out

Where a stretch has two count points with different figures, we publish the busier. That applies between Junctions 8 and 9, where the other count point records 69,749, and between Junctions 11 and 12, where it records 85,425. Where several count points share one figure — Junctions 5 to 6 and 10 to 11 — the figure appears once.

Six link roads are excluded from the ranking because they are not the M40 main line: the two links at M42 Junction 3A (51,574 and 47,908), the Junction 8 spur towards the A418 (66,274), the Junction 8 link to the A40 (26,844), the A40/A412 link at Junction 1 (78,017) and a short link from the main route to the A40 (13,317). Averages quoted elsewhere on this site across all 33 count points include them.

For the same stretches split by direction, see northbound and southbound. For lorries, see M40 lorry and freight traffic.

Traffic count figures on this page are from the Department for Transport road traffic statistics, 2025.