Police believe too much sunshine could be contributing to the violent road rage incidents caught on camera in New South Wales this week.

The explanation comes as eruptions of road rage prompted NSW Police to appeal for witnesses to a pair of shocking incidents, one of which is already heading to court.

A 41-year-old man who allegedly punched Bianca Lee Sams, 21, in the head at Lake Munmorah, on the NSW Central Coast, on Monday has been charged after surrendering himself at Wyong Police Station on Wednesday morning.

Dashcam footage posted on Facebook by witness Dwayne Pillidge on Monday made news across Australia and led to the charge of assault occasioning actual bodily harm being laid.

The unidentified man was granted conditional bail and will appear at Wyong Local Court on August 30.

Ms Sams admits flinging nails and a chisel at the man’s vehicle, claiming on her own Facebook page that he had been tailgating the Mazda BT-50 utility in which she was a passenger.

“I threw them because I had to … [it was] what I had to do to protect me and my friend,” she told the Nine Network.

“We were both scared, We didn’t know what to do. We tried swerving … and he kept following us.”

In the second incident, also caught on video by a bystander, men from two different cars traded blows in the middle of the roadway during a peak-hour melee at Merrylands in western Sydney.

In the mobile phone footage, four men can be seen getting out of their cars and throwing punches in the middle of a busy road in Merrylands.

As the fight intensifies, one of the men delivers a flying kick while another has his shirt torn off.

The altercation ends without apparent injury to any of the combatants, but that was small comfort for Chief Inspector Phil Brooks, who speculated that weather could be a factor in the outbreak of aggression.

“People are wanting to get to their destination quickly. They’re very upset with a vehicle in front or alongside for whatever reason, and it’s them trying to bully other drivers in the hope that they can get ahead of the traffic queue,” he said.

“When there are different driving conditions, incredibly cold weather, raining and so on there’s less likelihood of these events occurring.”

-with AAP and ABC