To the Limit:
Points and penalties

Is there a single qualified motorist anywhere in the UK who has never broken a speed limit? It's easy to pick up a few extra miles per hour on a long downhill run even when trying to carefully observe the limit, and in fact it's just as easy to travel five or ten miles per hour over the limit on an open road without fear of being noticed. Many people happily go much faster. The ease with which a speed limit can be broken and the lack of consequences from most acts of speeding can make it feel like it's not really breaking the law.

The result is that speeding is one illegal act that's widely considered normal and more or less acceptable, and which the majority of the population have almost certainly committed wilfully and repeatedly. Many don't feel like they're doing anything wrong at all. They're civilised, law-abiding people; their vehicles are taxed and insured. They don't mix with the criminal classes.

But the truth is that, like many aspects of motoring law, speed limits are absolute and unforgiving. Any infringement, even by 1mph, is illegal. 71mph on an empty motorway with excellent driving conditions is still — technically at least — a criminal act, and puts you in the same club as people in eye masks and striped jumpers carrying sacks labelled "swag".

Not all crimes are equal

Luckily for those of us who might have once or twice accidentally hit 42 in a 40 zone*, speed limits are not actually enforced with that much precision. Speedometers aren't so accurate that a driver can be absolutely certain of their true speed, which would make a conviction for, say, 42 in a 40 limit very shaky. Law in the UK is also, in all sorts of respects, simply not interested in marginal infringements, and the principle of de minimis is legalese for the idea that the legal system has better things to do than prosecute people who make such a small infringement that it made no difference to anyone.

As far as your speedometer is concerned, the law says that it absolutely must not under-read (so it can't show a lower speed than the one you're doing) but it may over-read by 10% + 4km/h. Most manufacturers will calibrate speedos to sit partway between the true speed and that margin of error, so if you appear to be doing 30mph you could actually be travelling at anything between 25 and 30, and a readout of 70 could mean anything between 61 and 70.

If your speedometer says you're driving at the 50 limit, are you actually doing 43mph? Click to enlarge
If your speedometer says you're driving at the 50 limit, are you actually doing 43mph? Click to enlarge

This means that enforcement tends to start at a point some way above the number on the signs. Many police forces in the UK share an "enforcement threshold" of 10% + 2mph on top of the limit, below which they will take no action (though some police forces will enforce limits at a lower threshold). There is a second threshold beyond which the offence is considered sufficiently serious that the case will be sent straight to court. However, speeding is still speeding, and even if they decide not to pull you over for doing 55 in a 50 zone, police patrols are still very unlikely to give you a thumbs up as you go past.

Limit 10% + 2mph
Court summons
20mph 24mph 35mph
30mph 35mph 50mph
40mph 46mph 66mph
50mph 57mph 76mph
60mph 68mph 86mph
70mph 79mph 96mph

It's the cops

Traditionally, speed enforcement was exclusively done by police on patrol, and a pair of blue flashing lights in the rear view mirror was the first indication that a sly attempt to pick up the pace had been noticed.

Back in the 1920s, when the national 20mph limit was in force, police speed traps meant a police car or (more often) motorbike taking cover by the roadside, ready to burst out and pursue anyone tearing along at more than the very pedestrian limit. This type of enforcement still happens today — there are even special raised platforms by the side of motorways for exactly this reason — but speed limits vary and hard evidence is needed before the police can pull someone over.

The police still carry out speed patrols, as indicated by this "police speed check area" sign. Click to enlarge
The police still carry out speed patrols, as indicated by this "police speed check area" sign. Click to enlarge

Since the 1970s, police cars have been equipped with VASCAR (Visual Average Speed Computer And Recorder), a dashboard-mounted box of tricks that works in conjunction with pairs of markings painted on the road surface (usually circles, dots or squares). The police operate a control each time the potential speeder passes one of the markings, which are a fixed distance apart, and the VASCAR unit calculates the vehicle's speed between those points.

VASCAR is a simple and reliable system whose only flaw is that it can't catch anyone whose route avoids the specially measured road markings.

ProVida is slightly more advanced. Originally developed in Denmark in the 1980s, it's a computerised system that calculates the speed of both the police car and the vehicle it's following, records video and data from cameras to the front and rear, and plays back the video to let the speeding driver relive the moment they earned themselves a fine.

The video ProVida captures, with read-outs of vehicle speeds and other data across the image, is accepted as evidence in court and has spawned a whole genre of real-life car chase TV shows.

Modern police patrol cars are also fitted with ANPR (Automatic Number Plate Recognition) units, which aren't for catching speeders at all — instead they check vehicle registrations against the DVLA database to find uninsured, untaxed and otherwise dodgy vehicles.

Police traffic officers test their new VASCAR unit on the M1 at Scratchwood, 1975.

The police are increasingly stretched for resources, and need to make sure they make the best use of their time, which leads to a debate over whether they should be looking for speeding drivers as much, or even at all, when they could instead be catching the uninsured, the untaxed and the dodgy.

On the one hand, the value of a conversation with a police officer and the ability to apply some discretion to individual cases is key to build respect for the law.

On the other hand, these days we have machines that can catch speeders automatically.


In spring 1992, a Metropolitan Police traffic officer called Roger Reynolds switched on a strange battleship-grey contraption in south-west London. It stood on the pavement beside the A316 at Twickenham Bridge, pointing a radar detector, a camera lens and a flashbulb at the tail lights of westbound traffic. It was a prototype "Gatso" — Britain's very first speed camera.

The limit was 40, but drivers were given a real sporting chance with the camera only set to trigger at 60mph or above. In its first three weeks, it caught nearly 23,000 drivers travelling wildly over the limit. Speed enforcement would never be the same again.

A Gatso camera still guards the site of Britain's very first speed camera, on the A316 at Twickenham Bridge. Click to enlarge

A Gatso camera still guards the site of Britain's very first speed camera, on the A316 at Twickenham Bridge. Click to enlarge

The Gatso was a modified version of a system developed by Maurice Gatsonides, a Dutch rally driver. To make convictions watertight, Reynolds worked with the designer to build in a double-check. Originally it simply measured the vehicle's speed with radar, and took a picture if it was above a certain threshold; Reynolds painted a ladder of markings on the road and had the camera take two photos at a fixed interval, providing photographic evidence of how far the vehicle had travelled in a known amount of time and therefore proving its speed.

Many of the first motorists to be snapped demanded their day in court, but none had their conviction overturned.

Once the ruthlessness of the speed camera became common knowledge, it was no longer necessary for them to do much. In 2012, the AA estimated that of the thousands of cameras in the UK, fewer than 600 actually worked. Many were dummies, with just a flash unit wired up to a radar detector and no camera equipment at all. Others were working cameras with no film in them. Today the number of working cameras is probably higher as newer models are digital, sending photos back to base over mobile phone networks, so running out of film is no longer an option.

The original Gatso model is slowly being phased out for newer versions, and it's also now sharing the roads with Truvelos, Monitrons and others. It's also joined by the camera that seems to guarantee almost total compliance over long lengths of road: SPECS (after its manufacturer, SPEed Check Services), the average speed camera. Vehicles pass through ANPR checkpoints and their average speed is calculated between each pair. The only way a driver can guarantee they avoid a ticket is to stay at or below the limit the whole way.

Cameras needn't even be fixed to the ground any more. Mobile camera units tour many parts of the country, parked up at the roadside or lurking on motorway bridges, often recording speeds and taking pictures at such distances that, by the time a motorist has seen the van, it's too late to brake.

Police speed cameras: once, yes, but not any more. Click to enlarge
Police speed cameras: once, yes, but not any more. Click to enlarge

The effectiveness of cameras in moderating traffic speed (even if only on the bit of road immediately in front of the camera) means they've multiplied rapidly. In 2000 there were 1,700 in use nationwide; by 2007 there were nearly 5,000. But while they had initially been operated by the police, they were later transferred to local authorities who were allowed to keep some of the revenue.

Cameras have a large and vocal opposition, thanks to a general hostility towards automated enforcement limiting the freedom of motoring and a specific distaste for speed cameras becoming a revenue stream for public bodies. They're referred to by derisive nicknames — "yellow vultures" for SPECS cameras and "talivans" for mobile camera vans. Some groups, such as MAD (Motorists Against Detection), go as far as to vandalise camera installations, spraying lenses with paint or even setting fire to them. In 2007, things got out of hand when a mail bomb was targeted at the manufacturers of SPECS. But removal of speed cameras has never gained much traction as a political cause, and the cameras continue to proliferate.

A hearty endorsement

Anyone caught speeding — by whatever means — will find themselves facing harsher treatment than the £10 fine instituted back in 1861.

There's still a fine, of course, though it's much higher now — up to £100 for a single incident. Speeding also comes with an "endorsement" where three penalty points are added to the offending driver's licence. Unfortunately, where driving is concerned, points do not win prizes, and a score of 12 points within a three year period is rewarded with disqualification from driving.

Most speeding offences today are handled with Fixed Penalty Notices (FPN), which usually offer a discount if the driver pays up quickly and without dispute. They're routinely posted out after a speed camera has flashed its disapproval, but can also be issued by the police.

Your speed: 28mph. A good score but no points. Click to enlarge
Your speed: 28mph. A good score but no points. Click to enlarge

A more recent development is the Speed Awareness Course, offered as an alternative to drivers who have broken the speed limit but not by an outrageous amount. They are an attempt at driver re-education and try to encourage people to think twice before putting their foot down quite so firmly in future.

In some ways this is a positive development: for anyone who considers speed cameras to be a way of punishing the motorist, instead of encouraging good driving, the idea that those who break the law will be offered some positive advice and education ought to sound like a step forward. Counting against them is the perception that they parrot road safety slogans at a room of disinterested people who are only attending in order to avoid a fine and points on their licence.

Nonetheless, whatever message Speed Awareness Courses might be broadcasting, it's certainly reaching a wide audience. 1.2 million people attended one in 2015, according to TTC Group, who run many of them. That's a lot of fines not collected and a lot of drivers now officially Aware of Speed.

Put a lid on it

Not all vehicles are capable of speeding. Increasingly, mechanical limiters (or governors) are used to prevent the heaviest vehicles from getting carried away. They work by restricting the fuel supply to the engine, and tampering with them is illegal.

Heavy goods vehicles (with a maximum laden weight of more than 3.5 tonnes) have a limiter fitted as standard, preventing them travelling at more than 56mph. This slightly odd number makes more sense as a neat, round 90km/h, which betrays the law's European origin. That obviously doesn't stop articulated lorries from doing a sneaky 35 in an urban area, but it does put a cap on the highest speed they can achieve.

Stuck behind a truck? Most heavy vehicles are limited to 56mph. Click to enlarge

Stuck behind a truck? Most heavy vehicles are limited to 56mph. Click to enlarge

There are some obvious advantages to this. Huge lorries are difficult to manoeuvre and slow to come to a stop, and in an accident the massive force that they apply, thanks to their weight and their enormous momentum, can do a lot of harm. Limiting the speed that they are capable of reaching means limiting the damage they can do in a collision.

However, nothing is without its disadvantages. Driving "on the limiter" means the driver can put their foot as hard to the floor as they like and the vehicle won't go any faster. It's easy to lose concentration when regulating the vehicle's speed is no longer an option, and 56mph can be a tedious pace on an open motorway. It also makes it difficult for large vehicles to pass each other — the tiny differential in speed between them means overtaking can use up several miles of road and vast reserves of patience in vehicles stuck behind them.

More recently, coaches (and anything else that carries more than eight people) and mopeds have had limiters fitted too. Buses now have an automatically governed top speed of 62mph, while mopeds can't top 30mph, no matter how much their engines whine.

The future

So what happens next? If we're already installing limiters in vehicles, how long before we all get them? Possibly never. Something else is on the horizon that will have a far bigger impact, and the future is far from certain.

The driverless car is most definitely on the way. Controlled very precisely by computer, driverless cars will fastidiously obey every rule. It's hard to imagine any manufacturer programming their vehicles to break speed limits — to do so would leave them wide open to litigation and accusations of gross irresponsibility. But every restrictive technology is eventually undermined. Smartphones that forbid certain software get "jailbroken" with unofficial, third-party code. As soon as driverless cars are widely available, someone, somewhere will be writing software to speed them up.

One advantage of driverless cars may actually be their precision. Already, automatic trains travel at higher speeds than human drivers are permitted to do on the same tracks. No longer does a track safe at 43mph need a limit of 40 — the limit can now be 43, or even 43.5. In the future, it's entirely possible driverless cars will be subject to different speed limits to humans, and they could well be higher in some places.

There's also scope for computers to play a greater role while there's still a non-computerised, muscle-and-skeleton driver at the wheel. Reduced insurance premiums are already on offer for motorists who are prepared to have their driving style monitored with experimental software — either on dedicated devices or on smartphones — that tracks a vehicle's location and speed. In the coming years it may be increasingly common to carefully observe speed limits as a way of keeping the cost of driving down.

Is this National Speed Limit zone on the A224 an endangered species, or will driverless cars one day be trusted to go even faster here? Click to enlarge

Is this National Speed Limit zone on the A224 an endangered species, or will driverless cars one day be trusted to go even faster here? Click to enlarge

It may start to look like the future is a world where the freedom of using your own judgement to drive has been lost. To some that will be a devastating and unacceptable blow. To others, greater control over vehicle speeds might also mean an end to widespread reckless and dangerous driving, and serious progress in reducing casualties and deaths on the roads.

On the other hand, most adults in the UK are drivers, and what's unpopular with drivers is usually unpopular in Westminster. Talk of "snooping" and surveillance in all walks of life is met with suspicion and opposition. Perhaps widespread monitoring and limiting will be kept at bay by its sheer unpopularity.

We won't know for a while yet. But in the meantime, as we travel forward into the future, please do try to observe the speed limit.

* Not me, of course. Heaven forfend. Goodbye, officer.

Picture credits