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Drink driving case dismissed as Garda didn’t tell motorist he was detained at roadside.

Updated: May 18, 2023

17 April, 2023.

A DRINK DRIVING CASE was dismissed at Killarney District Court after a Garda gave evidence that he may not have told a motorist that he was being detained while waiting for a breathalyser.

Garda Moynihan gave evidence before Judge David Waters that he had encountered Mr K. driving along Countess Grove, Killarney on 20 November 2022.

Garda Moynihan’s evidence was very fair.

He told Judge Waters that he saw Mr K’s car “swerve onto the incorrect side of the road” before turning onto another road “without indicating”.

He used his lights and sirens to direct Mr K’s vehicle to stop, “which it did”. The time was approximately 2:50a.m.

He asked him for his name and address and said that he “got a smell of intoxicating liquor from his breath and [that] his speech was slurred”. He asked Mr K. if he had been drinking and Mr K. said that he had “had a few pints”.

Garda Moynihan told Mr K. that he was going to conduct a roadside breath test.

The test was conducted at the roadside at 2:58am. Mr K. failed the test at 2:59am and he was informed of this failure. Garda Moynihan stated that he arrested Mr K. at 3am for drink driving “and I placed him in the rear of the patrol car. He was fully compliant”.

He was taken to Killarney Garda Station and informed that he would be required to provide two specimens of his breath.

Garda Moynihan stated that Mr K. was processed in the station and a 20-minute observation period then commenced.


Note: when a person is arrested for drink driving, they may be required to provide a breath specimen. To ensure that any excess alcohol cannot interfere with the test result, a 20-minute period of observation is conducted. During this time a member of the Gardai must observe the arrested person for 20 minutes to ensure that they don’t eat, drink or smoke anything. Once this 20-minute period has passed they are brought to the Evidenser machine (for determining the concentration of alcohol in the breath) and required to provide 2 specimens of breath.


GARDA MOYNIHAN SAID that he placed a mouthpiece on the Evidenser machine and “made sure not to contaminate it” with his hands.

The reading was 56mgs.

The legal limit is 22mgs.

Mr K. was charged and released from custody.


In cross examination Patrick Horan put it to Garda Moynihan that Mr K. had been fully complaint.

Garda Moynihan agreed.

He asked Garda Moynihan what time he had first observed Mr K. and he said that it was approximately 2:45am.

He suggested that his first interaction was probably no later than 2:50am.

Garda Moynihan agreed.

He said that the roadside breath test was administered at 2:58am.

Again, Garda Moynihan agreed.

Mr Horan asked Garda Moynihan whether he had the breath testing device at the roadside when he stopped Mr K.

Garda Moynihan did not know.

“I don’t have a note of it in my notebook so possibly not” he said.

Mr Horan put it to Garda Moynihan that Mr K’s instructions to him were that when he was stopped, Garda Moynihan had asked, over his walkie talkie, to have a breath testing device (Drager Alcometer) brought to the scene.

“Again, I don’t have a note of that but that could have been the case”.

Mr Horan said that there was an 8-minute gap between Mr K. being stopped and the roadside breath test being completed.

“He wasn’t under arrest?”


“But he wasn’t free to leave?”

“I had made a demand for a breath specimen.”

“Was he told that he could be legally required to remain at the scene for up to an hour while a Drager device was brought?”

Garda Moynihan fairly stated that he did not believe so.

Judge Waters said to Garda Moynihan that Mr Horan was suggesting that the legal reason for the roadside detention of Mr K. had not been explained to Mr K. at the time when this detention period began.

Garda Moynihan accepted that this may have been the case.

IN HIS SUBMISSIONS MR HORAN asked the court to dismiss the charge against his client. He pointed that no statutory power had been invoked by Garda Moynihan to detain Mr K. at the side of the road, nor was the legal authority for this detention communicated to him.

The roadside detention had amounted, in fact, to an arrest.

He referred to the relevant passage of Mr. David Staunton’s book (Drunken Driving [2021]) which dealt with the power to detain people at the roadside for breath specimens.

He pointed out that various legal authorities had been consistent on this point over the years and referred to the High Court case of DPP v McCormack [1999] that a valid arrest was comprised of two elements: the decision to arrest someone and communication of this decision to the arrested person.

Judge Waters asked what the significance of this failure [to communicate the fact of the detention] was to the case.

Mr Horan said that the detention of Mr K. at the scene-in the absence of a lawful power communicated-was an unlawful detention and that the exclusionary rule (established in DPP v. O’ Brien [1965]) now applied: the evidence obtained after the unlawful detention was inadmissible against Mr K.

Mr Horan said that the detention at the roadside was unlawful and that therefore everything that happened afterwards, including the later arrest, was also unlawful. He said that the later requirement for a breath specimen in the station was similarly compromised.

“It is a condition precedent for a requirement for breath in the Garda station that the person be validly arrested in the first place he said. This was not the case.”

Judge Waters agreed and highlighted another concern that he had with the evidence. He said that while Garda Moynihan had given evidence that he had been careful not to contaminate the mouthpiece into which Mr K. gave a specimen of breath in the Garda station, he had not given evidence that he had produced a sealed mouthpiece, or new mouthpiece, “or some variation of that”.

Judge Waters dismissed the prosecution.

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