How does the M4 run on a Monday morning into Reading, or a Friday afternoon out towards Bristol and Wales? These pages answer that from our own record of National Highways' live speed data: we read the speed on every stretch of the M4 in England every five minutes and keep the average for each hour, westbound and eastbound.

Pick a day of the week below to see how the motorway moved on the most recent one, against the same day a week earlier and the speed National Highways normally expects. National Highways' data stops at the Welsh border, so these pages cover the M4 from Chiswick to the Prince of Wales Bridge. For the road right now, use the live M4 traffic flow map and the latest M4 traffic news.

M4 Traffic by Day of the Week

• M4 on Mondays
  Hour by hour, westbound and eastbound
• 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.