Under the Road Traffic Act 2010, a motorist who refuses or fails to comply immediately with a request from a garda at a checkpoint to undergo a breath test commits an offence.
If the person is prosecuted and convicted by a court, the maximum penalty under the legislation is a fine of €5,000 and a six-month jail term.
The garda has the power to arrest the motorist, without a warrant, if, in his opinion, the driver has committed an offence. The motorist will then be brought to the nearest garda station.
If the motorist pleads that due to a medical condition, such as asthma, or for any other reason deemed acceptable by the garda, he cannot complete the breathalyser test, the garda has the power to take him to a garda station and require him to give a blood or urine sample.
Mandatory alcohol testing was introduced in 2006.
The changes meant that a garda no longer needed to form an opinion that a driver had consumed alcohol.
Mandatory checkpoints must be authorised by a garda inspector and are designed only to test for alcohol on a driver's breath. They can be set up anywhere in a public place, approved by the inspector, including roads outside a pub, nightclub or any other establishment that serves alcohol.
They are often set up in locations where they will make most impact in reducing drink driving.