British Standard BS AU 145e for number plates

British Standard BS AU 145e:2018 is the primary reference of the technical standards of retroreflecting number plates for vehicles in the United Kingdom. It was introduced on 28 February 2018 to replace BS AU 145d, which had been the standard since 1 September 2001. The new standard was released primarily to improve Automatic Number Plate Recognition (ANPR) detection rates, which currently record 1.2 million misreads daily.


British Standard BS AU 145e is published by the British Standards Institution (BSI), which is a royally-chartered national standards body. The 30-page standard can be purchased from BSI’s online store for £88 (£176 for non-members).


A sample of a British vehicle registration mark


Specifications outlined in BS AU 145e


BS AU 145e contains a wide range of standards for manufacturers and distributors of number plates. They are also useful for vehicle manufacturers, car dealers, and even for private citizens who are thinking about tinkering with their personal number plates. The primary goal of BS AU 145e is to ensure a high level of visibility of number plates. Some of the standards included in BS Au 145e are:


(i) Vibration, marking, impact and bend testing


To ensure number plates can withstand the knock and bumps of British roads


(ii) Thermal, environmental, thermal-cycling, and artificial weathering tests


This exposes number plates to tests mimicking the British weather, as well as rapid temperature shifts


(iii) Corrosion, salt-spray, and solvent-resistance tests


Aside from chemical found in rain water, these tests ensure number plates will not be affected by chemicals from cleaning solutions


(iv) Photometry, reflection factor, luminance, and chromaticity test


These series of test ensure that the number plates display the required level of retroreflectivity and contrast, particularly in low lighting conditions. It also evaluates the retroreflective material (acrylic) used.


(v) Typeface and layout


Sets the type of font used (Charles Wright 2001), dimension (including spacing) and colours. The layout also includes specifications for supplier and dealer information.