The top speed you can legally drive on UK roads is 70 mph. So why can cars reach speeds of over 100 mph?
The European Transport Safety Council says that 26,000 road deaths happen in Europe every year, and speed is one of the key reasons. As a result of this research, new speed limiting software called the Intelligent Speed Assistance system (ISA), has been developed.
The software will be mandatory for all new cars from this year despite the UK leaving the EU.
We look at how speed limiters could impact your car insurance, and how the new system isn’t guaranteed to stop you getting speeding penalties.
What is a speed limiter?
As the name suggests, a speed limiter is a safety device that stops you from driving faster than the prescribed speed limit on that road.
A speed limiter device is different to cruise control, which helps drivers maintain a consistent speed and reduce fatigue on longer journeys.
When will speed limiters be mandatory?
From 6 July 2022, all new cars will need to have a speed limiter device fitted.
How do speed limiters work?
Intelligent Speed Assistance systems use either a video or a GPS-linked system to detect speed signs.
The system will then alert the driver if they’re going over the speed limit, and if the driver doesn’t slow down the speed limiter should intervene. It does this by limiting the engine’s power, rather than applying the brakes.
The car should then naturally slow down to the new speed limit..
Critics have expressed concerns that the signals employed by ISA systems can be irritating for drivers. In recognition of this, manufacturers are being given a number of different options to alert drivers.
- Speed control systems can automatically reduce the engine’s power
- Gently pushing the driver’s foot on the pedal back
- Using flashing visual signs, followed by audio announcements if the driver doesn’t slow down
- A visual symbol followed by pedal vibrations if the speed doesn’t drop
In December 2025, data will be assessed and decisions made around the best way for speed limiter devices to alert drivers.
Why are mandatory speed limiters being introduced in the UK?
Could the new system spell an end to speeding fines, too? It’s certainly possible, and it’s a feature that Ford has capitalised on when promoting speed limiters in its vehicles. But this also relies on the driver responding to the ISA alerts.
Matthew Avery, director of research at Thatcham Research, says:
“Many drivers want to remain safe and drive within the law, however changing from one speed limit to another can be difficult and distracting. In this respect, Intelligent Speed Assistance systems help to not only keep drivers safe but also legal.”
“The new automatic detection software spots walkers, cyclists and vulnerable road users.
“With the new software in place, people may feel safer and be more likely to walk or cycle.”
Do speed limiters mean I won’t get a fine?
Even if you have a speed limiter device fitted to your car, you’re still responsible for the speed you’re driving at. This means that if you’re caught speeding you could still be stung with a fine.
Avery warns that there are limitations to the technology when it comes to detecting speed:
“Speed signs can often be obscured or inaccurate, while GPS mapping can be out of date. Temporary limits and road works can confuse the system too.
“This could lead to speeding fines if the system isn’t picking up the limit correctly. And drivers will still be liable, whether they were relying on the system or not.”
The ETSC says that the technology used in ISAs has a high level of accuracy. It has the ability to detect temporary speed limits, digital signs and overhead signs.
ISAs also have an in-built function which means it can detect over-the-air updates to speed limit information.
But ultimately, the car’s speed is the driver’s responsibility, The ETSC says:
“ISA is a driver assistance technology: the driver, not the car, is responsible for obeying the current speed limit at all times.”
If the ISA detects a lower speed limit than permitted the driver would be able to override the system.
The same applies if the ISA detects a higher speed than allowed. The driver would have to slow the car to the correct speed.
Driving assistance tools like ISAs are there to ‘assist’ drivers, not take full control of the vehicle. So even with the system, you’re not guaranteed to escape speeding penalties.
Will the UK adopt speed limiters even though we've left the EU?
Yes. The Vehicle Certification Agency will continue to follow EU regulations. This means that even though the UK has left the EU, speed limiters will still need to be fitted to new cars.
Even if the rules didn’t apply, it’s unlikely that EU-based vehicle manufacturers would make models with additional different specifications just to please the UK market.
Will speed limiters affect my car insurance?
The European Transport Safety Council believes that the technology could reduce road collisions by 30% and deaths by 20%.
If those forecasts prove accurate, then as well as making the roads safer there should be fewer car insurance claims.
Fewer claims could see premiums fall. After all, insurers base their premiums on risk. And if there’s a lower risk of a claim being made, the cost of insuring your car could be reduced.
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Do I need to add a speed limiter to my car in 2022?
Not yet. The rules just apply to new cars.
ETSC has confirmed these systems don’t need to be retrofitted, so you won’t need to fork out to get one installed in your motor just yet. Speed limiter removal: is it allowed?
It is possible to switch off your speed limiter device. However you cannot permanently disable it - the next time you switch on the engine the speed limiter will be switched on again.
It’s also possible that the authorities might scrap the option of turning it off in the future.
By installing a speed limiter device and keeping it switched on as a default, the hope is more motorists will take advantage of the technology and road safety will improve.
However, even when the speed limiter is on, there are some circumstances when you can override it. An example of this is if you’re overtaking on a road where there’s a decrease in speed limit.
After alerting you, the car should automatically start to slow down. By pushing down hard on the accelerator, you can override the system and complete the manoeuvre safely.
If you stay above the speed limit, the system should sound a warning and display a visual alert. The alerts remain on until the driver is within the speed limit.
What cars have speed limiters already installed?
Many models already use the ISA system, including:
Volvo has welcomed vehicle speed limiters, too. It was the first manufacturer to roll out the system across all its models. The company will cap the speed of all new cars at 112 mph.
Avery goes on to say:
“Euro NCAP has tested manual speed limiters since 2009 and has long promoted their fitment to new cars. In fact, most new cars now have ISA fitted as standard. In 2018 manually-set ISA systems became a requirement as part of the five-star Euro NCAP rating for safety.”
Volvo is also developing ‘smart speed controls’ that should detect when a car is driving near a vulnerable site, such as a school or a hospital. It’s hoping to develop the technology to improve driver behaviour.