But while this probably applies to signs that we very rarely see, some drivers reckon “99 per cent” of people don’t know what his sign – that we’ve all seen loads – actually means.

 

 

In a post on Reddit, one driver shared a picture of the sign with the caption: “I’m convinced 99 per cent of drivers don’t know what this sign means.”

The sign in question is a circular one, made up of a white background with a single black line going through the middle of it at a 45-degree angle.

People quickly took to the comments to either admit they didn’t have a clue what the sign meant, or brag about their brilliant sign knowledge.

 

 

One person joked: “40mph until you reach the next village and a 30mph zone, where you continue to do 40mph…”

Another quipped: “It means ‘minimum speed – 80′”

A third commented: “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.”

And someone else recalled a girl at their old hairdressers thinking that it meant “go whatever speed you want.”

 

 

Concerning.

Anyway, what does the sign mean then? Well, yes, it is to do with speed limits and the speed you can drive at.

The RAC website explains: “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.”

 

 

So, it’s the old adage of ‘it’s a limit, not a target.’

Of course, the national speed limit varies depending on what road you’re on and what 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.

On dual carriageways and motorways, it’s 70mph but 60mph for goods vehicles and cars towing trailers or caravans.

If I were you, I’d imprint these speeds on your brain if they’d slipped your mind, not just for safety reasons but also so you don’t get caught out by cameras when you least expect it.