Defences for Refusing Drug Testing in South Australia

Roadside Drug Testing in South Australia

Refusing a roadside drug test in South Australia is a serious offence under the Road Traffic Act 1961 (SA), but there are specific circumstances under which a refusal may be legally justified. This article explores the defence of “good cause” under Section 47EAA(10) and provides insight into how courts interpret and apply this concept. Alternatively, drug driving charges can be won when the police do not follow the test procedures.

Roadside Drug Testing

Police in South Australia have the power to request that a motorist take a roadside drug test in certain circumstances in order to test for the presence of THC, MDMA, Methamphetamine and as of 2025, for the presence of cocaine. As such, when a person is stopped for suspected drug driving, they may be required to undergo a drug screening test, oral fluid analysis, or blood test.

Penalty for Refusing or Failing Roadside Drug Test

Refusing or failing a roadside drug test can have serious consequences.

However, Section 47EAA(10)(c) of the Act allows a defence if the refusal is based on “good cause.” The burden of proof lies with the accused, who must demonstrate this on the balance of probabilities.

What is the “Good Cause” Defence in South Australia?

The concept of “good cause” is a statutory defence that allows individuals to justify their refusal to submit to drug testing. The term is not explicitly defined in the legislation, but it has been clarified through case law. Courts assess this defence based on two factors:

• Subjective Belief – The defendant’s personal belief about the justification for refusal.
• Objective Reasonableness – Whether the belief was reasonable in the circumstances.

Notable Cases

1. Bottomley v Symons (1982) 31 SASR 18

In this case, the defendant refused an alcotest, believing his diabetes would result in a false positive. The court found:

• The belief must be subjectively held, but the defendant’s conduct in holding the belief must be reasonable.
• The court upheld the defence of “good cause” because the belief was rooted in specific and reasonable grounds.

2. Daire v Rollins (1982) 30 SASR 156

The defendant reasonably suspected that the police were denying his right to request a blood test. The court upheld:

• A magistrate’s finding that good cause was constituted by the defendant quite reasonably suspecting on the basis of things said that the police were deliberately denying him his right to a blood test.

3. Bormann v Coldwell (1986) 43 SASR 297

Here, the defendant refused a breath test to seek legal advice. The court rejected this as “good cause,” reasoning that:

• The legislation’s purpose to maintain road safety outweighs personal concerns like obtaining legal advice.
• Immediate compliance with police directions is essential for public safety.

4. Czerwinski v Hayes (1987) 47 SASR 44

The defendant believed that post-driving alcohol consumption could falsely elevate his blood alcohol levels. The court found this belief to be reasonable and ruled that:

• A soundly based belief, even if later proven incorrect, may constitute “good cause.”

5. Police v Ghuede (2007) 99 SASR 280

In this case, the defendant argued that the drug swipe test was used to collect DNA without consent. The court dismissed this claim, noting:

• The belief must be objectively reasonable, not speculative or unsupported by evidence.
• The defence was rejected.

How to Prove “Good Cause” in Court

To establish “good cause,” the defendant must:

1. Provide Evidence – Include medical records, witness testimony, or other documentation to support the belief.
2. Demonstrate Reasonableness – Show that the belief was based on factual circumstances, not speculation.
3. Act in Good Faith – Prove that the refusal was proportional and intended to address a legitimate concern.

What Does Not Constitute “Good Cause”?

Courts have rejected the following defences:

• Inconvenience – Refusal due to time constraints or discomfort.
• Fear of Incrimination – Concerns about self-incrimination do not justify refusal.
• Conspiracy Theories – Claims without factual basis, such as misuse of DNA, are inadmissible.

Limits of the Defence

While “good cause” is a recognised defence, courts are cautious about applying it too broadly, as it could undermine the purpose of the legislation. Chief Justice King in Czerwinski v Hayes warned that lax application could frustrate the intent of maintaining road safety. Commonly rejected claims include:

• Refusing to comply due to inconvenience or fear of incrimination.
• Beliefs based on conspiracy theories or unfounded assumptions.

How Talon Legal Can Help

Successfully arguing “good cause” requires a thorough understanding of the law and the ability to present a compelling case in court.

At Talon Legal, our expert traffic lawyers in Adelaide have extensive experience defending clients against drug driving charges and refusals to undergo testing. We can help you avoid a licence disqualification, demerit points, significant fines and will protect your rights.

Book a Free 30-Minute Consultation

Take Control of Your Defence Today If you have been charged with refusing a drug test. Book a free 30-minute consultation with Talon Legal, Adelaide’s trusted traffic lawyers, and protect your rights.