Both the field sobriety tests and blood and breath chemical tests can be given during a traffic stop and arrest but the chemical test is much harder to fight against in a court of law.
These tests are more objective, which means it is convincing evidence to the judge presiding over the case or a jury who has to deliberate the guilt or innocence.
In order for a DUI lawyer to win his/her case, he/she must get this evidence suppressed (meaning it does not get heard and is not admissible in court).
A major DUI defense strategy component is to fight the results of the Breathalyzer test.
Bear in mind that a Breathalyzer exam is used to determine the total of alcohol on a DUI suspect's breath.
It involves a number of instruments and methods.
There's not just one machine that will get the Breathalyzer results.
For that reason, some machines are more unreliable than others.
Your criminal defense attorney may bring this up when presenting your case.
If an officer wants to ensure the test is done right, the machine has to be calibrated right and he/she must follow certain procedures in giving the test to a DUI suspect.
If these rules are disregarded, the Breathalyzer results can be thrown out of court.
DUI attorneys will often defend their client on the terms that the officer incorrectly did the test and/or the machine was calibrated wrong.
A major point many attorneys have been able to successfully argue is that the machines often have high readings due to certain medical conditions.
A Breathalyzer machine checks for the amount of alcohol on a person's breath; thus whatever number it comes up with must be the same in the bloodstream.
The machine relies mainly on mathematics but there are many biological factors that can affect the numbers.
Now your attorney can argue for an absorption defense but this defense depends on when you were arrested and when the Breathalyzer exam was given.
Keep in mind that it takes alcohol nearly two hours to get into your bloodstream.
If the alcohol you drank hasn't reached your bloodstream, it hasn't been factored into your BAC number despite the fact that the machine detected it.
This means the officer will have an incorrect reading; albeit a wrong high reading.
In many states, you're allowed to refuse this test.
It can make the case easier to win in court but it can lead to additional charges.
In fact, some states have laws that state if you're a DUI suspect and decline to submit to a Breathalyzer, your license can be suspended.
It's important to remember that a DUI/DWI conviction can have lasting consequences for years and years.
You want to make it hard for the prosecution to prove their case so that these lasting consequences won't affect you.
In the majority of DUI cases, the results of a Breathalyzer are paramount to the prosecution's case.
Yes, they can hurt your case but it's not the end all/be all evidence to it; your attorney can challenge it.
Hire an experienced DUI lawyer to dispute the results in court.