1. The charge was that, on 13 May 2013 at 10.12 am at Yu Tung Road Cycling Track near lamp post AC 1509, the Respondent being a person riding a bicycle on a road did, without reasonable excuse, fail to comply with the requirement indicated by a traffic sign of the type shown in Figure No. 155 in Schedule 1 of the Road Traffic (Traffic Control) Regulations Cap.374G (“the Regulations”). Figure No. 155 is a cycling restriction sign and indicates that cycling is prohibited beyond the sign and that cyclists must dismount and push their bicycle if they wish to proceed beyond the point of the sign. 2. The Respondent’s case at trial was that she was honestly and reasonably confused by the sign and thought that it meant cycling was permitted. 3. The magistrate convicted the Respondent and imposed a fine of $500 by way of sentence. The Court of First Instance (CFI) quashed the Respondent’s conviction and set aside her sentence on the basis that there had been material non-disclosure of relevant materials. The CFI held that the Figure No. 155 sign was ambiguous, unclear and confusing. Therefore, the CFI held that it offended the principle of legal certainty and also gave the Respondent a reasonable excuse for failure to comply with the traffic sign in question. 4. On the prosecution’s appeal to the Court of Final Appeal, the focus was on the nature and scope of the offence of failing to comply with the requirements of a traffic sign and the limits of the statutory defence of reasonable excuse. Specifically, the issues were whether the meaning of a traffic sign depends on the cyclist’s subjective interpretation and, if not, whether her mistaken belief in its meaning constitutes a reasonable excuse for failing to comply with the requirement indicated by it. 5. The Court held that the offence is not a failure to comply with a traffic sign but with the requirement that the traffic sign indicates. The interpretation of the sign is not dependent on the cyclist’s subjective appreciation or non-appreciation of the meaning conveyed by it. Instead, the interpretation of the sign is approached taking in the meaning assigned to it by the Schedule of the Regulations. It is therefore no part of the offence that the sign alone must be interpreted, either by the cyclist or by a court, in order to determine what it is that the cyclist should or should not do. 6. The Court held that a consideration of the defence of reasonable excuse involves looking to three matters: (i) the matters said to constitute reasonable excuse must be identified; (ii) the court will then examine whether the excuse is genuine; and (iii) the court must make an assessment of whether that excuse is reasonable, which the court will do on an objective standard depending on the particular facts of the case. In applying the test, the Court held that the Respondent’s excuse fell short of the “reasonableness” requirement in (iii) because: (a) given that the prescribed meaning of the Figure No. 155 sign is that set out in Schedule 1 of the Regulations and not as determined either by the cyclist or by the court by reference to the sign alone, there is no room, objectively, to conclude that the Respondent’s honestly held but mistaken belief as to the meaning of the sign was reasonable; (b) there are a number of traffic signs, the meanings of which are not immediately apparent merely from looking at them. It would be a recipe for traffic chaos if an honest belief that those signs had different meanings to those set out in the relevant Schedule of the Regulations could constitute a reasonable excuse for not complying with their requirements; (c) the meaning of a prescribed traffic sign being that set out in the relevant Schedule of the Regulations and reproduced in the Road Users’ Code, it is a simple matter for any cyclist to ascertain the meaning of any applicable traffic sign; (d) all users of the road have a responsibility to familiarise themselves with the meaning of traffic signs and road markings, since this is important not only in terms of compliance with the Ordinance and Regulations, but also from the perspective of road safety; and (e) it was contrary to the general principle that ignorance of the law is not a good defence. 7. The Court considered that whilst the non-disclosed materials might have been relevant to the “genuineness” requirement in (ii), they were not relevant to the “reasonableness” requirement in (iii). The Court also found that the principle of legal certainty simply did not arise as an issue and the CFI erred in holding that it was engaged in the context of the present case. 8. The Court unanimously allowed the prosecution’s appeal on the issues of law raised.