A woman and a three-year-old girl were seriously injured when they were hit by a "bin lorry" in Wolverhampton.
The crash close to the Grand Theatre led to nearby Lichfield Street being cordoned off as investigations are carried out.
The girl was taken to hospital alongside the woman, aged in her 30s, who has a suspected broken leg.
The lorry driver was treated for the effects of shock at the scene.
Traffic diversions, which have been in place since the collision at 11:00 BST, have been affecting the city's university graduation events at the theatre.
Wolverhampton University tweeted to advise people about an alternative route to the venue.
West Midlands Police described the vehicle as a bin lorry and said its investigation was at an early stage.
Both patients were taken to Queen Elizabeth Hospital, Birmingham, before the child was transferred to Birmingham Children's Hospital.