Police in the US are continuing to investigate a devastating accident that took the life of Australian broking leader Tim Wedlock and injured three others.

Mr Wedlock was crossing a street in Nashville, Tennessee, with a group of other pedestrians at 12.30pm on August 1, local time, when a car allegedly ran a red light and hit them.

Metropolitan Nashville Police Department says officers are working “to determine the cause of the 87-year-old driver’s actions”. The driver has been named as Thomas Cahill of Bowling Green, Kentucky. Police say he did not show any “indicators of impairment”.

“His 2013 model Ford Fusion struck pedestrians in the crosswalk, fatally injuring one of them and causing serious injuries to three others,” a police statement said.

Related article: Tributes flow for Tim Wedlock

A 44-year-old man from Florida and 58-year-old woman from Tennessee were in a critical condition. A 21-year-old woman from Tennessee had non-life-threatening injuries.

Mr Cahill was travelling with his 90-year-old wife, and both were in hospital with non-life-threatening injuries.

“Also in the car was the wife’s care-giver, who was uninjured,” police added. “She was interviewed by traffic division investigators and reported she was on her phone in the back seat when she looked up as she heard the pedestrians being struck.”

Mayor of Nashville Freddie O'Connell described the incident as “incredibly tragic”.

“Right now, it's unclear why the 87-year-old driver failed to stop for the pedestrians in the crosswalk,” he said.

insuranceNEWS.com.au will continue to monitor developments in the US.