Swedish police said on Monday that they had launched an investigation after the structure fell down in central Stockholm, injuring three people.
The iron gantry was torn down by a lorry with a mounted cherry picker at 2.30pm on Sunday outside the popular Västermalmsgallerian shopping centre on the Kungsholmen island in the Swedish capital.
It crushed on to a car and the lorry and blocked the busy Sankt Eriksgatan street for hours.
A man named only as Fredrik and his 18-month-old son Wille were in the car when the gantry came crushing down. They both escaped with only minor injuries.
“I only thought of my son. That I had to get my son out,” he told the Aftonbladet tabloid late on Sunday evening.
“On the one hand it's the maximum of bad luck to have this kind of thing happen to you. But how likely is it that you survive unscathed? It feels totally insane.”
The car and the lorry which ripped down the road sign. Photo: Sören Andersson/TT
The driver of the lorry was also taken to hospital. His condition was not known.
Police said on Monday that they were investigating the incident.
“We will look at what happened and investigate if a crime was committed. A lot of witnesses saw this. They are going to be heard and then we'll have to make an overall assessment,” Stockholm police officer Annie Hult told the TT newswire.