Stopped for a breathalyser test: what every driver should know

A breathalyser test is a procedure with strict rules. Its result becomes the central piece of evidence in the case, which is why what is usually challenged is the way the test was carried out — not the stop itself.

The limits

A driver is considered intoxicated with more than 50 milligrams of alcohol per 100 millilitres of blood, or above 240 micrograms of alcohol per litre of exhaled air. For new drivers, drivers under 24 and professional drivers the threshold is far lower — 50 micrograms per litre, which is effectively zero.

What can happen at the roadside

The officer may suspend the licence administratively for 30 days. In a number of cases the vehicle is also taken out of use, even where the driver is not its owner. A court summons follows, and on conviction the law provides for disqualification of at least two years, a fine and often a suspended sentence.

How the test works

A preliminary device is used first; it only indicates the presence of alcohol. The main instrument is then used, and it is its reading that goes into the file. A set interval must pass between drinking and measurement, and the procedure requires a specific number of breaths and a correctly functioning device.

Your rights and how to behave

You have the right to consult a lawyer.
Nothing prevents you from recording the test on a dashcam or by other means.
Do not refuse the test: refusal is treated as driving under the influence once the officer has explained what refusal means.
Be polite and follow instructions — the place to argue is the court, not the roadside.
Read what you sign before signing it.

What to note during the procedure

The mouthpiece should be replaced in your presence; if it was not, try to document that.
Record how long the test took and the intervals between stages.
Note the make and serial number of the device, the time and the officer’s details.
Ask for your remarks to be entered in the report on the spot, not afterwards.

What the defence examines

The calibration certificate and the working order of the device on the date of the test; whether the waiting period before measurement was observed; the number of breaths and how they were recorded; whether rights and cautions were explained beforehand. Where blood was taken, who took the sample, how it was stored and when it was analysed are examined separately.

Medical factors

Reflux, diabetes, respiratory illness, alcohol-containing medication and mouthwash all affect a breath reading. None of this is an automatic answer to the charge, but it is a basis for demanding a blood test, which is regarded as more reliable. Say so immediately rather than months later.

First steps afterwards

The administrative suspension runs while proceedings continue and is challenged by a separate application to the traffic court, heard within days. That is why it is worth speaking to a lawyer before giving your version, not after: what is said and signed at the roadside follows the case all the way through.

This article is general information and does not replace legal advice.