Average speed cameras - everything you need to know

The mysterious average speed camera. First introduced all the way back in 1999, average speed cameras have become a staple sight on UK roads.

But how exactly do they work? Lucky for you, we're here to explain exactly how these cameras work, how they track your speed and what you need to do to stay on the right side of the average speed limit.

How average speed cameras work

Like all mysterious things, average speed cameras in the UK are based on maths.

They come in a set of two (at least 200m apart) and work by calculating the time it takes for you to travel between them. The first camera registers your car and licence plate as you go by, and then the second one works out your average speed from how long it takes for you to reach it.

This creates a 'zone' of speed control, making them much more effective at keeping drivers at the correct speed than traditional speed cameras, which can be fooled by people speeding and then rapidly slowing down (running the very real risk of cars ploughing into your rearend).

Average speed camera tolerance explained

As you might expect when confronted by speed limit laws, the first question out of most people's mouths is, “How much can I go over the limit without being penalised?” The general assumption is that you won't be fine as long as you don't go beyond the '10 per cent + 2', which is explained further down.

The fact is that, as with all speed limits, whether or not you're prosecuted for going over the limit is down to the sole discretion of the police of that region. This means you could be fined for going over the limit by a few miles per hour, or for going over the limit by a lot.

However, it is generally safe to say that, if during the 20 miles of speed-controlled road works, you slip past the limit by a single mph, you won't have the entire police force clamouring for your wallet.

What are the potential penalties for speeding?

The minimum penalty for speeding is £100 along with three penalty points added to your driving licence. Drivers within two years of passing their tests will be given six points on their licence. An accumulation of 12 points will result in a driving ban.

From April 2017, fines of up to £1,000 can be given for speeding, rising to £2,500 on a motorway. The level of fine and the number of points added to your licence depends on the seriousness of the speeding. There are three bands of speeding fine.

What do average speed cameras look like - UK?

Now we know how average speed cameras work, let's check out some of the different types available. There are a few different variations of average speed cameras depending on the area that they are located in, but generally, all versions work on the principle of registering number plates and mathematically working out the car's speed.

SPECS average speed cameras

The SPECS camera is the one that you are most likely to come across. These are installed along the side of the road and are easy to spot thanks to their bright yellow colour.

Normally found next to road works, these cameras can be temporarily set up or permanently installed depending on the situation. Multiple SPECS cameras are needed at each point, as they can only monitor one lane at a time.

Vector average speed cameras

An upgrade on the traditional SPECS camera, the Vector camera not only accounts for vehicles' speed, but it can also monitor other driving violations, such as cars in the bus lane or running red lights.

In terms of speed violations, it operates exactly like the SPECS camera, registering a vehicle's licence plate and then mathematically working out its average speed. However, unlike the SPECS, one Vector camera is capable of monitoring multiple lanes.

SpeedSpike average speed cameras

One of the newest versions of average speed cameras, these high-tech speedster catchers are connected by GPRS, meaning that up to 1,000 of them are communicating to each other and registering number plates.

This means that, rather than just a stretch of road, a whole area can be monitored by this system and ensures that drivers are behaving themselves at every point. Not only that, but further technological advancements in speed cameras means that one SpeedSpike camera is able to keep track of multiple lanes on both sides of the road, making them extremely efficient.

Where are average speed cameras found?

Typically, average speed cameras can be found in large areas that require careful driving. As opposed to traditional cameras, which focus on a single key point in the road (such as at a dangerous turning or when entering a village), average cameras are used to enforce an extended period of speed control.

This can be in areas to protect vulnerable pedestrians, such as around schools or parks, or it can be used to ensure that there is a constant and reliable stream of traffic at potential bottle necks, such as at road works. Other places you will find average speed cameras include:

• Dual carriageways
• Motorways
• A-roads

You will be able to tell an average speed camera is on the road as you will see signs displaying a camera like the one pictured below.

Average speed check cameras - are they effective?

It's hard to know exactly how effective average speed cameras are, but the data is there to say that they have a strong positive effect on dangerous roads.

One of the best examples of this can be found on the A9, which, at one point, was one of the most dangerous roads in the UK (and nicknamed 'The Killer A9'). After some hefty campaigning, the UK Government installed a massive speed control section - the largest in the UK - in an attempt to save lives and keep motorists from driving at excessive speeds.

This went live in 2014, and, according to Transport Scotland, has seen a strong reduction in fatalities, along with a massive reduction in drivers speeding. There are further plans to make the entirety of the A9 a dual carriageway, which will further help enhance the safety of this road for drivers.

And, despite the grumblings of a speedy minority, the average speed zone has generally improved the journey time for most people using the A9 and reduced anti-social driving behaviours.

Average speed camera myths

10% plus 2

This myth isn't unique to speed cameras, but rather to speed limits in general. The idea is that you won't be fined for going over the speed limit as long as you don't go 10% plus 2 above the limit. For example, in a 50mph speed limit, you won't be fined as long as you don't go above 57mph.

The truth of this is that it is entirely up the police force, and they are fully justified in prosecuting anyone who goes even 1mph above the speed limit.

Changing lanes confuses speed cameras

As SPECs cameras only monitor one lane at a time, there is some truth to this myth. However, there is no way to know which camera is monitoring which lane, and cameras are now set up to overlap, meaning that they are covering more lanes than before. It's not worth the risk.

Plus, newer cameras, like the Vector and SpeedSpike, are becoming much more common and are capable of monitoring multiple lanes, so no amount of lane hopping will protect you from them.

It's all about money

Average speed zones are actually there to stop people speeding. A common misconception is that average speed cameras are only put in place to generate revenue and catch people out. The truth is that, since 2007, all revenue collected from average speed camera fines goes straight to the HM Treasury, and not the police.

Average speed zones cause more frustrated driving

Typically, average speed zones make driving less stressful because they help enforce a constant speed for every driver. Therefore, average speed zones help to prevent traffic jams. Check out this excellent animation from the Massachusetts Institute of Technology (MIT) which highlights phantom traffic.

Your questions answered

Do average speed cameras flash?

Unlike traditional speed cameras, average speed cameras don't flash if they detect someone going over the limit. This is due to them using infrared radar to read and register licence plates, meaning they can see perfectly no matter the light or weather conditions!

Do average speed cameras work in both directions?

The original SPECS cameras will only work in one direction and roughly one lane, but to combat this, there will be additional ones added to ensure that all parts of the road are covered.

The more up-to-date models are capable of monitoring multiple lanes and multiple directions. Generally, it's best to assume that every part of the road is covered.

Can average speed cameras catch you on your phone?

The most common average speed camera, the SPECS, will only monitor speed violations. However, the more recent additions to the average speed camera lineup will also pick up other traffic violations, such as being in the bus lane, running red lights, and, of course, driving while on your phone.

Do average speed cameras allow 10 percent tolerance?

The 10% tolerance is a common myth on the road and is certainly not unique to average speed cameras. The fact of the matter is the same for all speed limits: there is no hard and fast rule. It is up to the police's discretion when it is suitable to prosecute someone going over the limit, and this might be at 9mph over the limit, or even 1mph over the limit.

Your best bet is to not risk it and stick to the limit.

Do average speed cameras work at night?

Average speed cameras work at night, in bad weather, when the road is busy, when the road is empty; average speed cameras are just always working.

Are average speed cameras always on?

It is normally safe to assume that, if you see an average speed camera, it is on and it can see you. There is only one exception to this rule. If average speed cameras have been set up for some roadworks, there may be a few days after the roadworks are finished where the cameras are still set up.

In this very unique situation (or any other reason for the cameras not to be working), there will be 'Average cameras not in use' signs informing you that the cameras are not working. Beyond this, yes, the cameras are always on.

Do average speed cameras take pictures of the driver?

Average speed cameras are capable of a lot of things, but they don't take pictures of the driver. This means that, if you are caught by an average speed camera, you will have to fill out a form identifying the driver at the time.

Conclusion - the fool-proof way to avoid a speed camera ticket

Stay under the speed limit. That's it.

No really, this is the absolute best way to avoid tickets. No matter the camera, no matter the situation, if you stick to the speed limit, you're going to be fine (rather than fined).

Plus, sticking to the speed limit has a bunch of other useful benefits, including better fuel economy and lower running costs. Ultimately, a few miles per hour can be the difference between life and death in an accident.