One roadside test (over 20 minutes after last drink) which you either pass or fail. If passed, no further action. if failed then the driver is arrested and taken to the police station, where ONE more test is taken using the electronic equipment. Pass that, then no further action. If failed, there are two courses of action. Depending on the reading, it is either a straight fail (the reading is high), or the accused is then asked to provide blood or urine for a lab test and it depends on the result whether you are prosecuted. There are never three breath tests.