A person under arrest for driving while intoxicated understands the serious financial, legal and social consequences if convicted. Fortunately, there are some defense strategies that may result in a not-guilty charge.
There are various defense arguments, depending on the specific situations, but some are more common than others.
Lack of probable cause
According to the Texas Constitution and Statutes, a law enforcement officer may make an unwarranted arrest if there is probable cause. In cases of a DWI, this may include an officer pulling the defendant over for violating a traffic violation, a DWI checkpoint, a collision investigation or the observation of a driver swerving.
FindLaw discusses that one of the most common defense strategies is to argue that the officer did not have a justifiable reason for the initial traffic stop.
Increasing blood alcohol concentration
One argument is that the BAC of the driver while operating the vehicle was below the legal limit and that it only rose to .08 or higher between the initial stop and the breathalyzer test.
Accuracy or administration of a test
Another common strategy is to question the legitimacy or accuracy of one of the sobriety tests. One may argue that there was an improper administration of one of the field tests, such as the nystagmus test. It is not uncommon to argue that the breathalyzer was not calibrated correctly, which resulted in inaccurate results or that there were ensuing factors that messed up the results. If there was a blood test, one might argue that there was mishandling of the specimen or that someone may have tampered with it.