One of the most commonly misunderstood road rules in NSW has wreaked havoc again in the comments of a simple social media quiz.

NSW Road Safety asked its followers on Sunday a seemingly simple question about a hypothetical situation on the roads relating to zipper merging.

Which car must give way? Picture: NSW Road Safety
Which car must give way? Picture: NSW Road Safety

Merging is number four on NSW's list of the ten most commonly misunderstood road rules.

"When a driver is travelling on a road without lane markings and the number of lanes or lines of traffic is reduced, they must merge by giving way to any vehicle that is ahead of them. This is often called a zipper merge," NSW Road Safety notes.

This would mean that in the above diagram, car A has right of way over car B as the lane markings have ended and A is ahead.

The misunderstood road rule lived up to its name in the comments though as many people got the answer wrong despite being determined that in fact they had got it right.

Car A has right of way. Picture: NSW Road Safety
Car A has right of way. Picture: NSW Road Safety

"Hopefully B, but these days road rules are a lucky dip with the amount of people getting their licence on eBay," one driver lamented.

"I've been driving for 30+ years," another person commented before giving the wrong answer.

Others took issue with the design of the question itself.

"There is a flaw in this road design. It may be too late for Car A to realise the end of lane as the sign appears at the end of lane (high chance of collision with Car B) Car B may not be aware that two lanes are merging as there is no sign on the right hand side," they pointed out.

"All I know is most cars never allow me space to merge in," another person said.

"I have been in the situation, I think both have the same right, courtesy is the best way, slow down and let them go, any side you are," another commenter said ambitiously.

Another said "the number of incorrect responses reinforces the need for continued testing after drivers have their licence".

Originally published as Confusion over basic road rule