UK speed camera tolerances revealed

As research confirms that speed cameras have a tolerance, or ‘buffer zone’, drivers are warned that taking advantage of this might land them with a fine.

Speed cameras in general cause no end of confusion for motorists.

How accurate is a speed camera? Is that camera actually turned on? Is it a speed camera or just a traffic cam? What's the difference between average speed cameras and a mobile speed camera?

And one of the more common questions is do speed cameras have a bit of leeway before they flash you?

According to research by Auto Express, the answer to this last question is ‘Yes – they do’.

By the way, the idea that all speed cameras flash is a myth – many of them catch you with infra-red instead. So, unfortunately no flash doesn’t automatically mean no speeding ticket!

Speed camera over a busy motorway


UK speed camera tolerances

So how many mph over the speed limit can you go?

Auto Express contacted 45 UK police forces. Of the 33 that responded, 25 shared information about when their speed cameras activate if a driver is going above the speed limit.

Most police forces have a tolerance of 10% plus 2 mph above the limit before a speed camera ‘flashes’. So on a 30 mph road, a camera wouldn’t normally activate unless a car drove past at 35 mph or faster.

On a 70 mph stretch of motorway, the threshold would go up to 79 mph.

Here are the replies of the 33 forces that responded:

Police force Speed camera tolerance
Avon and Somerset
10% + 2 mph
Wouldn't reveal threshold
Wouldn't reveal threshold
10% + 2 mph
10% + 2 mph
10% + 2 mph
Devon and Cornwall
10% + 2 mph
10% + 2 mph
Don't use a standard threshold
Greater Manchester
Wouldn't reveal threshold
10% + 2 mph
10% + 2 mph
Wouldn't reveal threshold
10% + 2 mph
10% + 3 mph
10% + 2 mph
10% + 2 mph
Metropolitan Police / TfL
10% + 3 mph
10% + 2 mph
North Wales
10% + 2 mph
10% + 2 mph
Wouldn't confirm if threshold exists
Northern Ireland
10% + 2 mph
Wouldn't confirm if threshold exists
South Wales
10% + 2 mph
South Yorkshire
10% + 2 mph
Wouldn't reveal threshold
10% + 2 mph
Thames Valley
10% + 2 mph
10% + 2 mph
West Mercia
10% + 2 mph
West Midlands
Wouldn't reveal threshold
West Yorkshire
10% + 2 mph

This ‘buffer zone’ exists in order to improve driver safety. It means that drivers don’t have their eyes fixed on their speedometer instead of the road.


Do average speed camera tolerances work in the same way?

Will you get caught speeding if you’re one mile over, five miles, or 10? Speeding limits are there for a reason and anything over the limit is breaking the law. But how strict are average speed cameras? 

The research also shows that the average speed camera’s tolerance is 10% plus 2 mph for most police forces. 

But this is just an average and even going one mile an hour over the limit could result in a penalty. 


How much over the speed limit can you go before getting a ticket?

Motorway speed cameras or mobile speeding vans are all doing one job. Looking for drivers going over the limit.

You could be hit with a penalty if you’re over the speed limit even if there is a buffer zone in place.

Of the police forces that wouldn’t reveal their cameras’ buffer zones, two refused to acknowledge that a buffer even exists.

So although it might be tempting to assume that similar thresholds are in place everywhere, you could still be hit with a fine and penalty points on your licence.

It’s also dangerous – speed limits are there for a reason in the first place.

It’s also worth remembering that the buffer zones – where they exist – are used at the discretion of the police to follow the rules around speeding, speed cameras, and the law.

So they’re within their rights to punish drivers that flout the speed limit by even just a few miles per hour. You can’t rely on these discretionary thresholds as a defence if you’re flagged for speeding.

Mobile speed cameras might be calibrated differently, anyway. So you should never assume you can just sail through them marginally above the speed limit.


How many cars can a speed camera van catch at once?

Mobile speed cameras can catch speeding vehicles in either direction, coming towards or away from the speed camera van. Only one car can be captured at any one time, but the technology works incredibly fast. They can usually record a car’s speed quickly and move onto another vehicle.


What are the penalties for speeding in the UK?

If the offence is minor, you might be asked to go on a speed awareness course rather than take the fine and points.

For more serious offences, though, that option isn’t on the table and you face a fine, points on your licence and a possible ban.

In 2017, the rules on speeding fines changed, and they’re now based on a percentage of your weekly income, with the minimum fine being £100. The median weekly UK income last year was £586.

This is in addition to getting points on your licence. Our speeding fine calculator lets you work out any potential fine.


Do I need to tell my car insurance company about a speeding ticket?

Yes - you have to declare any speeding convictions or points on your driving licence to your car insurance company.

Although points remain on your licence for four years, insurers use them in their calculations for five.

As a result, you could see your car insurance premiums hiked up because insurers might deem you to be a bigger risk

According to research by Consumer Intelligence, a speeding conviction adds £50 to your annual car insurance premium, on average.

That’s an additional £250 to pay while that conviction remains on your record.

The research also found that motorway speeding offences increased premiums by more than £100 a year.

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