The penalties for getting behind the wheel while impaired by alcohol are severe in Texas, and even offenders who have never been in trouble with the law before lose their driving privileges for a year and can spend up to 180 days in jail. Prosecutors usually rely on police reports and toxicology data to establish intoxication in drunk driving cases, but this evidence is not always reliable and may be challenged. Motorists who are charged with driving while intoxicated could also admit that they were drunk but mount an affirmative defense.
Police departments use extremely sophisticated equipment to conduct breath tests, but these devices may be inaccurate if it they are not recalibrated regularly and maintained properly. In 2019, judges in New Jersey and Massachusetts dismissed 30,000 drunk driving cases because of questionable breath test results. Blood tests are considered to be more reliable than breath tests, but even this evidence could be challenged by DUI and DWI defense attorneys if prosecutors are unable to show a clear chain of custody.
Most drunk driving cases begin with a traffic stop, which can be a problem for prosecutors if the police officers involved took action without a reasonable suspicion that a crime had been committed. In these situations, drunk driving defendants could argue that the traffic stop violated rights protected by the Fourth Amendment and DWI charges should be dismissed. Motorists could also mount a drunk driving defenses based on police misconduct if the officers involved failed to follow official procedures when they conducted field sobriety or breath tests.
Affirmative defenses are used in DWI cases when the defendant admits that they were operating a vehicle while intoxicated. The most common affirmative defenses in DWI cases are necessity and involuntary intoxication. A drunk driving defendant could mount a defense based on necessity if they were acting to prevent a greater harm, and they could claim involuntary intoxication if they did not know the drinks they consumed contained alcohol. The facts of every DWI case are different, and drivers and their attorneys should study them carefully before deciding on a defense strategy.