If the police stop you on suspicion of driving under the influence (DUI) of alcohol they may ask you to take one or more tests. The results of these tests could be used against you in court to show that alcohol was affecting your driving or that you were above the legal limit.
Some tests happen roadside and some after an arrest, at the station or a designated facility.
Field sobriety tests
Field sobriety tests are the weakest of all the tests. They are not scientific, rather the officer decides whether you pass or fail by looking at how you perform. There is generally no advantage to you taking these tests, and, as they are not obligatory it is usually best to refuse.
Breathalyzer test
Officers may have a portable test unit in their vehicle. Or they may ask you to take a test back at the station. Either way, breath test results are not easy to dispute. You’d need to look at whether the machine was calibrated per schedule, whether the officers administered the test correctly and whether any external substances affected the reading.
Blood tests
A blood test usually gives an accurate, scientific reading of your blood alcohol. It cannot tell how you were driving, but it can show you were over the limit.
Urine tests
Urine tests, if conducted, would also take place after arrest. Once again they are not infallible, but it would take a strong argument to dispute the results.
If you know you were over the legal limit, disputing the accuracy of a test may be tough (although it is still worth considering). However, you may still have options to dispute the charges on procedural technicalities, for example. Getting help to explore all options will be essential.
