When it comes to a drunk-driving conviction, the primary piece of evidence used to convict offenders will be a DWI blood test that shows a result over .08, the Missouri blood alcohol limit. This is typically done by a breath test but may also be the result of a blood draw.
So it often comes as a surprise to defendants to learn these tests are far from infallible. In fact, significant errors are commonplace.
In Missouri, accused drunk drivers may face charges of driving while intoxicated (DWI) as well as driving with an excessive blood-alcohol content. Driving with an excessive blood-alcohol content is the “per se” equivalent of DWI - if you have a BAC above the legal limit of .08 you are considered per se guilty of the violation. “Per se” means “by itself,” meaning that fact alone presumes guilt.
These charges are different and require different defenses. The state’s burden of proof is also different in each case. The chemical blood, breath or urine test is enough to convict for a BAC charge, while a DWI charge may be proven by a totality of the evidence, even without a valid chemical test.
In this way, Missouri has attempted to increase the chances of conviction for those who refuse to take the test. Or, conversely, in cases where test results are clear but significant issues otherwise exist involving other circumstances of an arrest. Like in most states, Missouri law will also automatically suspend the driver’s license of a driver who refuses to take the test. However, unless you are certain you will pass – which typically means you have consumed fewer than 2 alcoholic beverages - taking and failing the test just gives the state a critical piece of evidence it can use against you.
Field sobriety tests are another way officers attempt to collect evidence against you. Despite the fact that there are only three standardized field sobriety tests - the nystagmus test (pen test), the one-leg stand, and the walk and turn – law enforcement officers are notorious for attempting to put suspects through “road-side Olympics.” These tests are meaningless, are not required by law, will only make you look foolish on police video, and should therefore not be taken.
Your drunk driving defense lawyer in St. Louis can challenge a DWI or BAC charge on any number of fronts. Challenging blood-alcohol content test results is among the most complex areas of defense. When successful, a significant reduction or outright dismissal of the charges often results.
It’s important to distinguish between portable breath tests that officers may give a suspected drunk driver at the scene, and the machine testing that occurs once a suspect has been taken into custody. Portable breath tests are not admissible in court as proof of guilt. This is an often misunderstood area of law. A 2017 appellate court decision in Missouri made portable breath tests sufficient as probable cause for arrest. But not as proof of blood-alcohol content in court. Additionally, it’s important to note that a portable test below .08 may also be used to support the defense.
There are many ways an experienced St. Louis DWI defense lawyer can challenge BAC results, including:
The length of time between arrest and testing.
There are many defenses to drunk driving charges. Challenging BAC results can be a significant part of building a defense in some cases. But an experienced St. Louis DWI defense attorney will have many other ways to fight the charges, from challenging probable cause for the traffic stop, to questioning each step of the arrest process.
Even in cases where solid evidence of guilt exists, an experienced DWI defense attorney can work within the system to seek a reduction in charges or to minimize the consequences of conviction. Drunk driving is among the most frequently charged serious traffic violations in Missouri. The state hopes you will simply plead guilty and attempt to put the incident behind you. However, the consequences will follow you for years, including the inability to work in certain jobs and the very serious enhanced penalties if you are stopped and arrested again.
Contacting an experienced law firm is the best thing you can do to protect your rights and to put the incident behind you for good.