As crimes often involve the use of motor vehicles, Automatic Number Plate Recognition (ANPR) systems are becoming an essential technology for police in many countries.
The interesting thing is that many people have no idea that the police use such technologies. Licence-plate reading cameras are sometimes very inconspicuous, or even completely hidden, such as in lightbars and inside vehicles.
However, even police officers using these systems do not know much about where and when the ANPR technology was developed, or about its impressive list of successes.
Here are some interesting facts about ANPR that few people know.
As ANPR systems require relatively advanced cameras, computing power, and software, few people would guess that the technology was developed more than forty years ago by the Police Scientific Development Branch in the United Kingdom.
Pilot testing was done in the late 1970s on the A1 motorway connecting London and Edinburgh as well as in the Dartford Tunnel. In 1981 the licence-plate detection technology helped in arresting the first vehicle thief.
Of course, these were static systems installed on roads rather than mobile systems which, due to miniaturisation and technological progress, are commonly installed in the smart police vehicles of today.
ANPR systems are proving to be so effective in combating crime that, in addition to deploying and expanding the technology, some countries are adapting their licence plates to make them easier to read by camera.
For example, in the Netherlands they changed the design of some characters (such as R and P) at the beginning of the millennium. These letters now feature a small gap specifically designed to make recognition easier. ANPR technology has helped to reduce speeding offences in the country by 90%, which then translated to significant accident reduction, the saving of lives, and the prevention of property damage.
Today’s top ANPR cameras can read licence plates with a high reliability, even from a moving police vehicle in normal road traffic: i.e., under constantly changing conditions (speed, light intensity, or varying weather conditions affecting visibility). Regardless of the difficulties, this small detail further enhances camera reading efficiency.
Most people would probably think that if ANPR can check hundreds of licence plates per minute, even at highway speeds, it cannot be a problem for them to also measure the speed of vehicles. Right? Well, in most cases this is not true.
ANPR cameras are not yet used as a replacement for radars. However, vehicles fitted with ANPR capability can be relatively easily and cost effectively upgraded to include speed detection functionality. The cost of adding such a functionality to a modern smart vehicle is about half the cost of today’s mobile vehicle radars.
ANPR systems are usually associated only with car theft detection, which is the original function these systems were developed for. However, the usefulness of technology has been proven to go far beyond its original purpose in recent years. For example, it has helped to clarify some murder cases, including the murder of police officer Sharon Beshenivsky, who was shot dead during a robbery.
In the Netherlands, ANPR is used to also identify tax evaders and seize their vehicles. And in the UK, where an extensive network of more than 10,000 static and mobile ANPR cameras collects around 50 million licence-plate readings a day, they detected more than 750,000 vehicles without compulsory insurance in 12 months.
As most crimes somehow involve the use of a vehicle, some police officers have referred to the ANPR as a revolutionary technology: “I believe that this is the best investigative tool we have had since the introduction of DNA analysis,” said Geoff Dodd, the regional programme director for joint policing in Yorkshire.