
01Section
The first eighteen miles
Leaving Mayfair, Kensington or Chelsea, we normally get onto the M4 at junction 1, using the A4 or the Hogarth roundabout. From the City and Canary Wharf, the car heads west along the A40 and the A406 instead, and before 09:00 the choice between them makes a fifteen-minute difference.
Between junctions 3 and 5, all the different kinds of Heathrow traffic share the motorway at the same time. This managed-motorway stretch has variable speed limits and hard-shoulder running, so which lanes are open can change with little warning.
Once you're beyond junction 8/9 at Maidenhead, traffic drops off steeply. The final regular pinch point is Reading at junction 11; after that, the road gives no trouble for the next seventy miles.








