Thousands of UK drivers may be unknowingly putting themselves at risk of fines and penalty points due to a habit many don’t realise is an offence. A recent survey found that 1 in 10 drivers do not rely on their speedometer to judge their speed, instead using other methods such as SatNav readings, instinct, or keeping pace with surrounding traffic.
While 86% of drivers surveyed said they check their dashboard speedometer to ensure they are staying within legal speed limits, 14% admitted they primarily use alternative methods. Among these, 8% rely on SatNavs or phone apps, while the remaining 6% use either their own judgement or the speed of other road users.
Why This Could Result in Fines
Using anything other than the car’s built-in speedometer can lead to serious consequences. SatNavs and mobile apps, while useful for navigation, rely on GPS signals to estimate speed, meaning they can sometimes provide inaccurate readings. This margin of error could result in drivers unknowingly exceeding the speed limit and receiving fines or points on their licence.
Mark Trimbee, CEO of private plate supplier Regtransfers, warned: “SatNavs rely on GPS readings to calculate speed, and while they’re often accurate, there’s always a chance the reading could be wrong, since accuracy is determined by the quality of the satellite signal being received.”
He also highlighted the dangers of using instinct or the speed of other drivers as a guide: “30mph can feel like a crawl after being on the motorway, and it can be all too easy to misjudge your speed. As for using other road users to judge your speed, this one’s simple—if they’re over the speed limit, you will be too.”
The Legal Requirement for Speed Awareness
UK law requires that a vehicle’s speedometer must be accurate and always display a speed equal to or slightly higher than the actual speed. By law, a speedometer:
- Must never understate a driver’s speed.
- Can display up to 110% of the actual speed but no higher.
This means that if a SatNav or phone app underestimates speed, a driver could exceed the limit without realising it. Relying on personal judgement or other road users further increases the risk of unintentional speeding violations.
Avoiding Unnecessary Penalties
To stay compliant with the law and avoid fines, drivers should:
- Always check their speed using the dashboard speedometer.
- Use SatNav speed readings as a secondary reference, not a primary measure.
- Avoid basing their speed on traffic flow or personal judgement.
With over 42 million full driving licence holders in the UK, even a small percentage relying on inaccurate speed judgments translates to millions of drivers potentially at risk of fines. Ensuring that speed is monitored correctly is essential for both legal compliance and road safety.
