Location : The M4 westbound between junctions J18 and J19 . Reason : Accident involving an overturned vehicle. Status : Currently Active. Time To Clear : The event is expected to clear between 20:30 and 20:45 on 29 June 2021. Return To Normal : Normal traffic conditions are expected between 20:30 and 20:45 on 29 June 2021. Lanes Closed : There are lane closures.