ANPR system: number plates as vehicle access credentials

What is an ANPR access control system?

An ANPR access control system uses automatic number plate recognition to identify vehicles at a site entrance and open the gate or barrier for the ones on its access list. It is the same camera technology used by the police and by car park operators, put to a different job: here the number plate works like an access card, and your access control system decides who gets in.

For the background on how the cameras read plates, see what is ANPR on our blog. For car parks that also need a live space count and a FULL sign, see the ANPR car park barrier system.

How the ANPR system works at your gate

1. 1

   The camera reads the plate

   As a vehicle approaches, the ANPR Lumo reads its number plate at 2 to 10 metres, using its built-in infrared illuminator.

2. 2

   The plate becomes an ID

   The camera turns the plate into a Wiegand ID and sends it to the access control panel, exactly as a card reader sends a card number.

3. 3

   The panel checks it

   The panel checks the ID against the access list, with the same access levels and time periods it applies to cards.

4. 4

   The barrier opens

   If the plate is valid, the panel opens the gate or barrier and records the event. If it isn't, the barrier stays down.

The ANPR Lumo can also run on its own. Its web software holds time-based white, black and ignore lists, so a single gate can work without a separate access control panel.

Number plates or vehicle tags?

ANPR and long-range RFID tags both identify vehicles without the driver stopping. The choice comes down to who the vehicles belong to and how much administration the site wants.

Some sites use both. At Exeter Science Park each entry and exit lane has a uPASS long-range tag reader, used as the main credential, and an ANPR camera. Our blog compares the two in more detail: long-range RFID vs ANPR, and the car park access control system page sets tags, plates, cards and QR codes side by side.

Manage plates alongside cards and fobs

• One system for people and vehicles: number plates are registered in Norpass3 like any other credential, so there is no separate vehicle system to run
• Authorised in advance: a visitor's or contractor's plate can be added before they arrive, without the vehicle being present or a tag being posted
• Access levels and time periods apply to plates in the same way as to cards
• No outside lookups: plates are managed like any access control credential, with no reference to the DVLA or other external bodies and no service fees for plate data

ANPR camera hardware

• Nedap ANPR Lumo, which we distribute and support: an all-in-one camera with embedded software, analyser and infrared illuminator. It reads plates at 2 to 10 metres across a lane up to 3.5 metres wide, uses deep learning to read different plate fonts, and is rated IP65 for −20 to +55°C. Outputs are Wiegand, RS485 and Ethernet, with a REST API for software integration.
• ANPR stainless steel posts, designed and manufactured in South Wales: the SSP-ANPR holds the camera at 585 mm, the right height for standard plates, and the SSDP-ANPR adds red and green traffic lights driven at 24 V from the access controller or barrier logic.
• Barriers and gates come from the barrier or gate manufacturer; the sites in our case studies use CAME and FAAC barriers.
• Access control: Norpass3 with CRC22x controllers, or the access control system the site already runs.

Works with your existing access control

Because the camera sends each plate as a Wiegand ID, the format a card reader uses, it connects to most access control panels without changes to the software. At George Spencer Academy, Advanced IT Services added Nedap ANPR to the school's existing Paxton Net2 system. At North West Ambulance Service's Lancashire headquarters, Expert Security UK connected it to a centrally controlled barrier system, where each valid plate is checked centrally in the same way as a card. For deeper software integration the camera also offers RS485, Ethernet and a REST API.

ANPR and UK GDPR

A number plate that can be linked to a person counts as personal data, so the organisation running the site is responsible for it under UK GDPR. In practice that means saying why plates are collected, putting up signs at the entrance, deciding how long plate reads and images are kept, and limiting who can see them. The ANPR Lumo has 10 GB of on-board storage for reads and images, so include it in the retention policy. The ICO's guidance on video surveillance covers ANPR.

What affects the cost of an ANPR system

• The number of lanes, since each lane normally has its own camera
• Whether exits are read as well as entries
• Stainless steel posts or wall and pole mounting
• New barriers or gates, or reusing the ones on site
• Connecting to an existing access control system or installing Norpass3, which is licence-free
• Groundworks and cabling between the lanes and the controller

Our blog has a fuller breakdown in how much an ANPR system costs. We supply through installers and distributors, so the price for your site comes from the installer after a survey. Our sales team can help put the equipment list together: sales@nortechcontrol.com.