Guidance

Amendments to the speedmeter, traffic light and prohibited lane enforcement camera handbook (amendment A) (accessible version)

Updated 18 December 2024

Applies to England, Scotland and Wales

October 2024

© Crown copyright 2024

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Version history

Amendment	Purpose / Change	Date
A	Text amendments to provide further clarification on documented requirements	Oct 2024

Introduction

Scope

1. This documentation is intended for participants in the Road Traffic Law Enforcement Devices Home Office Type Approval (HOTA) system (excluding equipment which is used to support law enforcement when assessing levels of alcohol and banned substances in drivers).

Purpose

2. This document provides amendments to requirements detailed in The Speedmeter, Traffic Light and Prohibited Lane Enforcement Camera Handbook v2.0^{[footnote 1]}

3. Feedback on the content of this document, including new amendments or requests for further clarification, should be submitted to:

[email protected]

Amendments to ‘The Speedmeter, Traffic Light and Prohibited Lane Enforcement Camera Handbook v2.0’

4. The following items provide amendments to ‘The Speedmeter, Traffic Light and Prohibited Lane Enforcement Camera Handbook v2.0’.

5. Each section contains the original text from the existing handbook (v2.0) followed by the amended text.

Item 1: Section 5.9.1 Second method of speed measurement

Original text

A. An independent second method of speed measurement shall be used to verify the primary speed measurement. Independence shall be taken to mean electronic, electrical and physical isolation. The measurement shall if possible, involve a different principle than that used for the primary measurement (such as two photographs or video frames taken a known time apart). The second method shall be independently accurate to within 10% of the vehicle speed, as determined by a reference speedmeter, acceptable to the Home Office, with ≤±1 mph measurement accuracy. An offence shall be rejected if the second method is not within 10% of the primary measurement. To test the accuracy of the second method the speedmeter shall be set up in traffic and at least 500 measurements shall be made in the most unfavourable configuration. A test track may be used for this purpose. During trials the second method shall be independently accessible for each vehicle passage: the output of the second method cannot be modified or filtered out by any comparison with the primary speed.

B. For automatic distance/time speedmeters a different principle may not be possible. If two images a known time apart are used for the second method of speed measurement, it shall use a different type of clock than that used for the primary measurement, and it shall have a different response to changing environmental conditions and to ageing. The time interval used in the second method shall coincide within 0.1 second of the start and end of the primary measurement. The second method shall be within 10% of the vehicle speed, as determined by a reference speedmeter, acceptable to the Home Office, with ≤±1 mph measurement accuracy. An offence shall be rejected if the second method is not within 10% of the average speed recorded by the primary measurement. The accuracy of this measurement shall be checked when each primary speed measurement is made under section 9.4.

Amended text

A. An independent second method of speed measurement shall be used to verify the primary speed measurement. Independence shall be taken to mean electronic, electrical and physical isolation insofar as practical and practicable. The measurement shall if possible, involve a different principle than that used for the primary measurement (such as two photographs or video frames taken a known time apart). The second method shall be independently accurate to within 10% of the vehicle speed, as determined by a reference speedmeter, acceptable to the Home Office, with ≤±1 mph measurement accuracy. An offence shall be rejected if the second method is not within 10% of the primary measurement. To test the accuracy of the second method the speedmeter shall be set up in traffic and at least 500 measurements shall be made in the most unfavourable configuration. A test track may be used for this purpose. During trials the second method shall be independently accessible for each vehicle passage: the output of the second method cannot be modified or filtered out by any comparison with the primary speed.

B. For automatic distance/time speedmeters a different principle may not be possible. If two images a known time apart are used for the second method of speed measurement, it shall use a different type of clock than that used for the primary measurement, and it shall have a different response to changing environmental conditions and to ageing. The time interval used in the second method shall coincide within 0.1 second of the start and end of the primary measurement. The second method shall be within 10% of the vehicle speed, as determined by a reference speedmeter, acceptable to the Home Office, with ≤±1 mph measurement accuracy. An offence shall be rejected if the second method is not within 10% of the average speed recorded by the primary measurement. The accuracy of this measurement shall be checked when each primary speed measurement is made under section 9.4.

Item 2: Section 5.9.3.11 Data Security requirements for automatic unattended devices

Original text

A. The authentication process shall follow that described in NIST Special Publication 800-38B for the CMAC Authentication Mode. All systems shall use CMAC with AES 128 and a MAC length of 128 bits.

Amended text

A. The authentication process shall follow that described in NIST Special Publication 800-38B for the CMAC Authentication Mode unless the device was developed under HMAC authentication guidance (historical). All systems apart from those developed under historical HMAC guidance shall use CMAC with AES 128 and a MAC length of 128 bits (or better). Devices developed under HMAC authentication guidance can use HMAC as defined in FIPS 198 used with SHA-1 or SHA-512 defined in the Secure Hash Standard FIPS 180-2. Otherwise CMAC Authentication Mode should be used as defined in the NIST Special Publication 800-38B.

Item 3: Section 5.9.3.17 Data security requirements for automatic unattended devices

Original text

A. Each site must have a battery backup so that, on detection of a failure of the mains supply, it can close down operations in a controlled manner maintaining the integrity and security of the stored data and enable operations to be automatically resumed when power is returned.

Amended text

B. Each site must have a secondary power backup not connected to the mains primary power supply, this can be in form of battery or other means, so that on detection of a failure of the mains supply the secondary power backup will close down operations in a controlled manner maintaining the integrity and security of the stored data and enable operations to be automatically resumed when mains primary power is returned.

Item 4: Section 5.10.2 Variable speed limits

Original text

A. The speedmeter shall enforce the displayed speed limit (or the National Speed Limit when none is displayed) only when both the following are true:

i. All the speed limit signs connected to it are correctly displaying the same speed limit, except when the hard shoulder of a motorway is actively managed and that lane may show either the same speed limit or a red X;

ii. The speed limit has been displayed for one minute or longer. This delay shall be variable to at least five minutes.

B. The speedmeter shall not enforce speed in the actively managed hard shoulder when the red X is displayed. It shall operate with, and only with, all speed limit signs mounted on the same gantry, facing in the same direction and over the same carriageway, and every one of these signs fully operational.

Amended text

A. The speedmeter shall enforce the displayed speed limit when all the speed limit signs are mounted on the same gantry, facing in the same direction, over the same carriageway and all the speed limit indications are identical, not subject to the faults in section 9.11 and the speed limit has been displayed for one minute or longer.  The one-minute enforcement delay shall be variable to at least five minutes. National Speed Limit may be enforced if any one of these conditions is not met.

B. The speedmeter shall not enforce speed in the actively-managed hard shoulder when a red X is displayed for this lane.

Item 5: Section 5.10.4 Variable speed limits

Original text

A. Within a variable speed limit, the time shown in photographs shall be within 10 seconds of a broadcast radio clock signal. On power-up, the speedmeter shall not commence enforcement until this synchronisation has been established. Enforcement shall stop whenever synchronisation is not maintained or is not confirmed with the radio clock within 14 days.

Amended text

A. Within a variable speed limit, the time shown in photographs shall be within 10 seconds of a broadcast radio clock signal (including GPS). On power-up, the speedmeter shall not commence enforcement until this synchronisation has been established. Enforcement shall stop whenever synchronisation is not maintained or is not confirmed with the radio clock/GPS within 14 days.

Item 6: Section 7.13 External aspect verification

Original text

A. Where visibility of the signs is greater than 300 m, external aspect verification, if used, shall always correctly recognise the number of variable message signs within the external verification image. For every sign it shall correctly recognise the aspect displayed, including when a blank aspect is displayed, or recognise when it is unable to do so. Whenever it is unable to recognise the aspect displayed on every sign, all enforcement shall be disabled, but speed may be enforced at the National Speed Limit.

Amended text

A. Where visibility of the signs is greater than 300 m, external aspect verification, if used, shall always correctly recognise the number of variable message signs within the external verification image. For every sign it shall correctly recognise the aspect displayed, including when a blank aspect is displayed, or recognise when it is unable to do so. Whenever it is unable to recognise the aspect displayed on every sign, all enforcement shall be disabled, except for speed which may either be not enforced or enforced at the National Speed Limit.

Item 7: Section 8.3.1 Part 1 – Conducted susceptibility testing as part of CE-marking and Section 8.3.2 Part 2 - Radiated susceptibility testing as part of CE-marking

Original text

A. Part 1 – Conducted susceptibility testing as part of CE-marking

B. This is taken from the CE-marking EMC test requirements and should therefore be performed in accordance with EN61000-4-6.

C. It covers conducted susceptibility induced by RF via cabling and it applies to all electrical and electronic equipment that have significant lengths of cabling attached during operational use. This usually applies to mobile or stationary equipment, irrespective of power source.

D. Level 3 of 10 Vrms is applied over a frequency range of 150 kHz to 80 MHz stepping through at 1% frequency increments using 80% AM (amplitude modulation) at 1 kHz.

E. Part 2 – Radiated susceptibility testing as part of CE-marking

F. This is taken from the CE-marking EMC test requirements and should therefore be performed in accordance with EN61000-4-3.

Amended text

A. Part 1 – Conducted susceptibility testing

B. This test should be performed in accordance with EN61000-4-6.

C. It covers conducted susceptibility induced by RF via cabling and it applies to all electrical and electronic equipment that have significant lengths of cabling attached during operational use. This usually applies to mobile or stationary equipment, irrespective of power source.

D. Level 3 of 10 Vrms is applied over a frequency range of 150 kHz to 80 MHz stepping through at 1% frequency increments using 80% AM (amplitude modulation) at 1 kHz.

E. Part 2 – Radiated susceptibility testing

F. This test should be performed in accordance with EN61000-4-3.

Item 8: Section 10.1.4 General requirements for all devices

Original text

A. A calibration certificate shall be supplied to the police force using the device, with a copy held on record by the person who has calibrated the device. In addition to device specific requirements listed later in this document, the calibration certificate shall include:

i. The name and company of the individual who undertook the calibration;

ii. The device manufacturer, type/model and serial number;

iii. The date on which the calibration was conducted;

iv. A certificate number and the date issued;

v. A statement to the effect that any parts or components replaced are identical to those used in the device as type-approved;

vi. The signature of the person who undertook the calibration.

Amended text

A. A calibration certificate shall be supplied to the police force using the device, with a copy held on record by a senior named person in the company supplying the device. This person will take ownership of the calibration records so they can be traced back to the individual that calibrated the device. This is to include the signature of the individual that conducted the calibration and this is to be kept within the company so it can be requested, if required, subject to GDPR.  In addition to device specific requirements listed later in this document, the calibration certificate shall include:

i. The name and company of the individual who undertook the calibration;

ii. The device manufacturer, type/model and serial number;

iii. The date on which the calibration was conducted;

iv. A certificate number and the date issued;

v. A statement to the effect that any parts or components replaced are identical to those used in the device as type-approved;

vi. A calibration code, which will be unique to the individual undertaking the calibration.

End of document

1. The Speedmeter, Traffic Light and Prohibited Lane Enforcement Camera Handbook v2.0. A guide to type approval procedures for devices used for road traffic law enforcement in Great Britain. 19 December 2022. collision reduction equipment (publishing.service.gov.uk) ↩