What is traffic sign recognition and do you need it?

Traffic sign recognition is the third eye you didn’t realise you needed, we explain how it works and its uses

James Wilson
Sep 28, 2021

Traffic sign recognition is an incredibly simple bit of technology, yet many drivers find it an extremely useful assistance tool. Cameras fitted to the front of the car are able to recognise signposts and notify the driver of speed limits and more via alerts on the car's digital display.

Chances are you know the speed limits and overtaking zones around where you live and work, but traffic sign recognition really comes into its own when you are driving somewhere alien to you. It can help you detect unexpected average speed zones for example, and basically help you to ensure you're following the rules of the road at all times, even if you do have a lapse in concentration.

Because it does happen to the best us. We’ve all been caught driving in an unknown area in amongst traffic and missed a speed limit sign or two. So, having traffic sign recognition can be a great safety net.

Plenty of used cars are equipped with systems like this these days, head over to the BuyaCar search page if you're keen to take a look at what's on offer.

How does traffic sign recognition work?

Without getting too geeky, most systems work using a forward-facing camera hidden behind your rearview mirror. They scan the road ahead and identify certain road signs. Most can read speed signs, but it is increasingly common to find traffic sign recognition systems, which can identify other road signs such as no-overtaking zones.

More advanced versions, such as that offered by Mercedes, will offer you the chance to jump to the new speed limit (with the press of a button) if you are driving using cruise control, while some Volkswagen models will automatically change to the new speed limit with adaptive cruise control enabled. There are even systems that will jump for you should you wish them to, so you never miss a speed change again – or in theory at least.

What are the benefits of traffic sign recognition?

The benefits are generally focused around driver convenience, which for many is great news. As mentioned above, it should take the stress off attempting to keep on top of speed signs when driving somewhere new.

Also, for those who spend a lot of time on the motorway where variable speed limits are becoming all the more frequent, many systems, such as Ford’s traffic sign recognition software, will identify speed limits displayed on motorway gantries.

What are the problems of traffic sign recognition?

Despite the advantages of traffic sign recognition, there are drawbacks. For starters, in more rural areas it is fairly common to see a traffic sign which has been engulfed by a hedge. Which could mean you and your car plough into a 30mph zone way above the speed limit, endangering other motorists and pedestrians.

Next time you are on the road, take a look at how many vans and lorries have little speed limit stickers on them. There have been reports of cars thinking these small stickers are the speed limits – not helped of course if motorists are driving too close to the rear of a van or lorry.

Normally these stickers say what the vehicle is limited to, which is fine on a motorway, but if you are in a built-up area, chances are you don’t want your car thinking the speed limit is 60 or 70mph. The worst case here is cars that automatically change to the new speed limit. That said, most cars of that capability will have adaptive cruise control as well, so will know there is a vehicle in front and not fly off to 70mph.

What comes next for traffic sign recognition?

As the technology becomes more widespread its capabilities will increase too, so it would be natural for the signs a car can identify to increase. There are also app-based traffic sign recognition systems for your Android, which could bring the technology to older vehicles.


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