Junction 2 is where the M3 meets the M25 at its own Junction 12, and it is the busiest decision point on the motorway. Nearly half of everything on the M3 at this point is heading for the M25 rather than continuing north to Sunbury.

How busy is the M3 at Junction 2?

The Department for Transport counts traffic either side of the M25 interchange. These are the 2025 figures.

How busy is the M3 at Junction 2?

Stretch	Length	Vehicles per day
Approaching the M25 (Kitsmead Lane flyover to M25 J12)	2.1 miles	113,905
Beyond the M25, J2 to J1 Sunbury (estimated)	5.8 miles	62,848

© M3Traffic.co.uk · Statistics from the Department for Transport

The gap between those two figures is the interchange itself: around 51,000 vehicles a day — about 45% of the traffic — join or leave the M3 at the M25. It is the single biggest exchange of traffic anywhere on the motorway.

The approach to the M25 is also noticeably one-sided: 60,584 vehicles a day westbound against 53,321 eastbound, a 14% difference. Lorries make up 7,713 a day, or 6.8% of the traffic.

The J2–J1 figure is marked Estimated by the Department for Transport rather than counted, so treat it as an indication rather than a measurement. Every other figure on this page is from a physical count.