This is the shocking moment a car crashed from a bridge, killing two passengers including a 97-year-old great grandfather.

The white Isuzu Mu-X was travelling along the Thanarat Bridge when it collided with a Nissan 350Z and plunged into the Mae Klong River in Ratchaburi province, Thailand, on February 25.

Dramatic footage shows onlookers screaming as the SUV nosedived into the water, sinking as two of its passengers swam to the surface.

Police Major Nattapong Ardaum of the Muang Ratchaburi Police Station said officers were notified of the accident at 5:40 pm local time.

They arrived at the scene, where the damaged Nissan 350Z driven by local bonsai expert Sittisak was blocking the road. A section of the bridge railing was also destroyed in the crash.

Rescuers tried to tow the Isuzu Mu-X onto the riverbank, but could only secure it with ropes due to the strong currents.

A crane was later dispatched to winch it out of the river.

Two injured survivors, the driver and a former district council chief in Pattani province, Supol, 69, and a female passenger Warawan, 57, were rescued.

However, Supol's wife Kruewan, 65, and father Pin, 97, were both killed in the crash.

Witnesses said the road leading up to the bridge had four lanes, which converged into two lanes on the bridge deck.

They said Supol had been trying to overtake Sittisak's sports car at the approach but crashed into it instead.

Following the first impact, Supol then reversed his SUV and crashed into the Nissan again before falling off the bridge.

Furious Nissan owner Sittisak said: 'This action could be seen as intentional murder because I had no prior acquaintance or disputes with the other driver. I welcome a thorough investigation by the authorities.'

Meanwhile, Supol claimed that he panicked after the initial crash. Fearing he would hit another car while reversing, he said he ploughed forward instead, causing the SUV to smash through the bridge railing.

Police Major Nattapong said: 'The deceased have been transported to the hospital. We will conduct an investigation following the legal process.'

Thailand has one of the world's worst road safety records. Ministers have set the goal of reducing fatalities from 32.7 deaths per 100,000 people to 12 per 100,000 people by the year 2027.

However, a lack of road safety education in schools along with notoriously easy driving tests, police failures to enforce road laws, and chronic under-investment in infrastructure, all appear to hamper the efforts.