Motorists convinced '99% of drivers' don't actually know what common road sign means

We’ve all got that mate who was first to pass their driving test and still won’t let you forget it.

You’d think they were a Top Gear host the way they bang on about their skills on the road, but it turns out not all of us are perhaps so wised up as we thought.

Some motorists are convinced ’99 percent of drivers’ in the UK don’t actually know what a common road sign means.

Sure, we all had to pass our theory tests before we could head out on the roads but maybe you took that test a while ago and didn’t quite keep up the full marks.

One motorist took to Reddit to express their frustration as they believe a lot of other drivers don’t have a clue what this particular, very common, sign indicates.

The sign in question is circular, featuring a white backdrop with a single black stripe through the middle at a 45-degree angle, with the Reddit poster saying: "I'm convinced 99% of drivers don't know what this sign means."

People took to the thread to offer their guesses, and jokes, with one quipping: "National speed limit, but what that limit is depends on what you’re driving.

"For example, if you’re driving a BMW it’s 100mph and excuses you from using indicators."

Another said: "There's a road near me with this sign and if you're averaging more than 30 down it you're either a complete plank or suicidal."

A third shared the rather worrying anecdote: "One of the girls at my old hairdressers genuinely thought it meant 'go whatever speed you want'."

So, what does the sign actually mean?

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The RAC website explains, saying: "A white circular sign with a single black diagonal stripe through it tells you that the national speed limit applies on the upcoming stretch of road. It supersedes any previous speed limit signs you may have had to adhere to, such as passing through temporary roadworks."

It adds: "Of course, even when the national speed limit applies, it might not always be safe to drive at that speed, so use your common sense on this."

This means you drive either at the speed limit, or the speed of the traffic on the road.

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Looking at you, drivers who weave between cars down the motorway...

But what is the national speed limit? Well, it depends on the road you are driving on and the vehicle you're driving.

In a built-up area with streetlights, the speed limit is 30mph unless otherwise stated. On a single carriageway it's 60mph for cars, and 50mph for vans and anything bigger, as well as if you're in a car towing something.

And on a dual carriageway and motorway, it's 70mph but 60mph for goods vehicles and cars carrying trailers or caravans.

So now you know, there are no excuses!