Video shows two cars collide after refusing to allow the other to merge on Port Wakefield Rd, at Bolivar

Two cars have collided after neither would let the other in front on a busy road – so who was in the right? See the video.

“Classic Adelaide merging.”

It’s a tale as old as – well, roads with multiple lanes. Adelaide drivers just don’t want to let cars merge ahead of them.

Where does it come from? Is it in our blood? Is it in the water? Is it because Glen Osmond Rd can never be widened enough? It’s a deep mystery that will likely never be explained.

Here’s the latest evidence from Dashcams Adelaide, which mused, is it really worth damaging your vehicles for?

Two cars have collided after both refused to allow the other to merge on Port Wakefield Rd. Picture: Dashcams Adelaide

But then again, as Tom wrote in a Facebook comment: “Unspoken rule of driving in Adelaide is to never let the other driver merge.”

So what is the official South Australian law?

SA's merging and give way rules when changing lanes.

The state government’s Driver’s Handbook is pretty clear, and even answers the age-old question that many Adelaide Hills dwellers and commuters seem to struggle with – who has to give way entering the freeway?

“If you are on a road where the traffic is merging from two lines to one line, you must give way to a vehicle on your left or right if any part of that vehicle is ahead of your vehicle. This is called the Zip Merge (example 38).

“The Zip Merge does not apply where lane lines are marked between the vehicles and one lane is ending (example 39) such as at the end of overtaking lanes and when entering the freeway.”

SA's merging and give way rules when changing lanes.

So it means drivers entering the freeway don’t have right of way if they’re in front – and need to get up to speed and merge into a gap.