On a Monday the M4 fills with Thames Valley commuting: drivers heading for Slough, Reading and Bracknell, airport staff around Heathrow, and people coming back east after a weekend in the West Country or Wales.

This page shows how the latest Monday went, westbound and eastbound, hour by hour. The cards pick out the slowest hour and the slowest stretch in each direction.

The M4 on Other Days

• M4 on Tuesdays
  Hour by hour, westbound and eastbound
• M4 on Wednesdays
  Hour by hour, westbound and eastbound
• M4 on Thursdays
  Hour by hour, westbound and eastbound
• M4 on Fridays
  Hour by hour, westbound and eastbound
• M4 on Saturdays
  Hour by hour, westbound and eastbound
• M4 on Sundays
  Hour by hour, westbound and eastbound

For the road right now, see the live M4 speed flow map and the latest M4 traffic news, or look up any junction on the M4 junctions page.