Plan extra time during rush hour; roads leading to Heathrow, including the M4, often experience congestion

https://telegra.ph/Central-London-to-Heathrow-StepbyStep-Directions-via-Tube-Train-or-Taxi-08-17

Plan extra time during rush hour; roads leading to Heathrow, including the M4, often experience congestion, especially around junctions and airport exits.