# The Road Vehicles (Construction and Use) Regulations 1986, Paragraph 7: Signal warning to driver


(1) A warning must be provided if the condition in paragraph 6(5) is met.
(2) The warning must be given by a visual signal or display text and must—
(a) be visible to the driver while the driver is in their designated seating position with their seat belt fastened;
(b) be yellow in colour if the detection system malfunctions;
(c) be red in colour if a single failure results in a hydrogen concentration exceeding 3.0% by volume in the air in the enclosed or semi-enclosed spaces of the hydrogen-fuelled vehicle;
(d) when illuminated, be visible to the driver under both daylight and night time driving conditions;
(e) remain illuminated if the ignition locking system is on the ‘On’ or ‘Run’ position, or if the propulsion system is activated, and—
(i) hydrogen concentration exceeds 3.0% by volume in the air in the enclosed or semi-enclosed spaces of the hydrogen-fuelled vehicle, or
(ii) a detection system malfunction exists.

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Source: https://www.legislation.gov.uk/uksi/1986/1078/schedule/5A/paragraph/7 (the official version)
Page: https://openlegislation.uk/road-vehicles-construction-and-use-regulations-1986/schedule-5A/paragraph-7
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.