Signalling left when leaving roundabouts


What is the statutory interpretation of the word ‘practicable’ in the context of Road Rules 2014 (NSW) (the ‘rules‘) s 118(1): ‘If practicable, a driver driving in a roundabout must give a left change of direction signal when leaving the roundabout’?

Hence, what defence can a driver argue to the charge of breach of s 118(1)?


In Potter v Neave (1944) SASR 19, 21 (‘Potter’), Mayo J held that ‘[p]racticable may be paraphrased as capable of being done or accomplished with the available resources whatever they may be’. Moreover, the Potter definition is consistently applied in the Work Health and Safety Act 2011 (Cth) s 18, with the words ‘reasonably able to be done’. However, in the NSW jurisdiction, the Potter definition may be persuasive, but not binding.

Interpretation Act 1987 (NSW) s 33 requires:

In the interpretation of a provision of an Act or statutory rule, a construction that would promote the purpose or object underlying the Act or statutory rule (whether or not that purpose or object is expressly stated in the Act or statutory rule or, in the case of a statutory rule, in the Act under which the rule was made) shall be preferred to a construction that would not promote that purpose or object.


The inclusion of the words ‘[i]f practicable’ in the regulation may infer that there are some contexts where the signal may not be required.

However, on the proposition in Potter, a reasonable person would expect that if a signal device is fitted to a vehicle, then a driver would be ‘capable’ of using it to ‘give a left change of direction signal when leaving the roundabout’.

Furthermore, in seeking the purpose of the statutory provision, no absurdity appears when using the plain and ordinary meaning of the words in the context of the statutory provision; thus, further aids may not be required to arrive at the intention of the parliament and comply with the Interpretation Act 1987 (NSW) s 33.

Although, as the rules are subordinate legislation, it may be reasonable to consider that the intention of the parliament is to delegate the drafting of the rules to the executive branch of government. This is especially the case with these rules, as this codified instrument has significant level of detail that the parliament may not be equipped to validate. Ironically, that would not be practicable for the parliament. Therefore, the executive agency who has been delegated responsibility may be able to provide extrinsic aid to assist in determining the mischief the regulation was introduced to suppress, or at least provide some clarity on the rules.

In December 2016, Transport for NSW Centre for Road Safety published a document titled: Top 10 misunderstood road rules in NSW. On the topic of ‘Exiting a roundabout’ they wrote:

Just like exiting any road, drivers must signal left when leaving a roundabout, if it is practical to do so, and stop indicating as soon as they have exited the roundabout. When travelling straight ahead on a small single lane roundabout, it may be impractical to indicate left when exiting.

The definition of the word ‘impractical’ may provide some guidance on this matter. The Australian Concise Oxford Dictionary defines impractical as ‘not adopted for use or action; not sensible or realistic’.

A reasonable person may consider it not ‘sensible or realistic’ to indicate left when exiting in some roundabout contexts. For example, where the left signal is activated at a point in time where it does not provide any useable notice to surrounding road users. This example may arise due to the size of the roundabout, and thus, this is consistent with the context ‘small single lane roundabout’ prescribed in the publication.

However, the Centre for Road Safety provides this disclaimer:

This document does not constitute legal advice and is provided only as a guide to the Road Rules 2014. Road users must ensure they are familiar with the Road Rules and comply with the requirements prescribed in law.

On 14 November 2012, parliamentary debate occurred in the NSW Legislative Council concerning this matter, but no clarity can be taken from that. See page 16756.


Unless a driver can argue that he or she is not ‘capable’ of ‘[giving] a left change of direction signal when leaving the roundabout’, then a judge may hold that the signal is required.

However, consistent with the advice from the Centre for Road Safety, the regulation may not be applicable in certain roundabouts. Irrespective of the disclaimer, a judge may find it reasonable that a driver relies on the advice in the publication.

Want to learn more?

If you want to learn more about this topic, consider upgrading your driver licence to either Medium Rigid, Heavy Rigid, or Heavy Combination, or perhaps enrol in our Advanced Heavy Vehicle Driver Training course.

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Michael Sciberras

Michael is the Chief Executive Officer at ALLTRUCK DRIVER TRAINING. He has 16 years of heavy vehicle training and assessment experience, and is currently studying law at the University of New England.

Disclaimer: This article must not be relied upon for legal purposes.