A bus driver and his passenger escaped unhurt after a large tree toppled over and crushed their vehicle along with three other cars.

The driver Choi, 62, and his passenger, a nanny, were on their way to pick up kindergarteners when the massive flame tree on the pavement of the Ho Man Tin neighbourhood in Kowloon District, Hong Kong, fell over on September 16.

Dashcam video captured their brush with death as the tree's trunk smashed into the bus's windscreen, missing Choi in the driver's seat by mere inches.

The tree also struck the roof of a Mercedes-Benz, with its driver climbing out of her car to survey the damage.

Speaking to local media, Choi said: 'I was waiting for the green light, suddenly there was a shadow, and then the tree collapsed in front of me with a loud bang.

'The situation was very chaotic, but fortunately, I got only scratches, no major injuries.'

The nanny said she suffered scratches to her feet after being hit by glass shards. Both of them received first aid from paramedics and were not hospitalised.

Authorities said three other cars were damaged.

Ken So, chief executive of the non-government Conservancy Association, said the tree likely collapsed due to decaying roots.

He said: 'The tree's roots have very serious decay. So actually, there was no big root providing anchorage for the tree.

'As there are no obvious defects or signs that can be found above ground, the problem is underground. Likely it was caused by various road or utility works that damaged the roots.'

Following the incident, the Leisure and Cultural Services Department said it will conduct an investigation and regular checks on roadside trees to ensure public safety.

Hong Kong is a former democratic British trading island on the outskirts of China.