Video from the United States shows the moment a cyclist who ignored warning signs as a bridge was opened to let a boat through fell into the gap between the roadway and the leaf of the bridge bring raised.

The incident happened on the Racine Street Bridge – a bascule bridge, similar to Tower Bridge in London – in Menasha, Wisconsin, following a Fourth of July firework display, reports wsaw.com.

Footage supplied by the Wisconsin Department of Transportation shows lights flashing as the gates are lowered ahead of the bridge being raised.

But the cyclist ignores them, pedalling through the gates, hitting them with her backpack as she does so.

Moments later, she falls into the gap. More than a minute later, people come to her aid, one checking her condition, another appearing to phone for help.

According to wsaw.com, the bridge was kept open until the cyclist, a 37-year-old woman, was taken to safety.

Police said that she was subsequently taken to hospital to be treated for facial injuries.