The prosecution in an Indiana OWI case relies heavily on chemical test evidence, field sobriety test performance, and officer observations to establish that a defendant was operating while intoxicated. What most defendants do not realize is that each of these evidence types has known vulnerabilities, that Indiana law establishes specific requirements for their admissibility, and that an experienced defense attorney who understands these requirements can identify arguments that may suppress, discredit, or contextualize the prosecution’s evidence in ways that significantly weaken the case.
Field Sobriety Tests: Standardized Protocol and Its Violations
The three Standardized Field Sobriety Tests endorsed by the National Highway Traffic Safety Administration are the horizontal gaze nystagmus test, the walk-and-turn test, and the one-leg stand test. NHTSA’s validation research for these tests was conducted under specific controlled conditions, and the tests are only reliable as evidence of impairment when administered strictly according to the standardized protocol. Deviations from that protocol, including incorrect instructions, improper demonstration, or failure to account for physical conditions that affect performance, can invalidate the test results.
An experienced Indianapolis DUI Attorney will obtain the arresting officer’s training records, review the body camera footage of the field sobriety tests, and evaluate whether each test was administered in compliance with the NHTSA protocol. Any significant deviation is the basis for a challenge to the admissibility or weight of the test results.
Breathalyzer Reliability: The Technical Case for Challenge
Indiana law requires that breath test devices be approved by the Indiana Department of Toxicology and that they be operated by certified operators using approved procedures. The certification and calibration records of the specific device used in your case must be obtained and reviewed by the defense. If the device was not properly calibrated within required intervals, if the operator’s certification had lapsed, or if the required operational procedures were not followed, the test result may be excludable. Why SOC 2 Compliance Is More Than Just Automation also emphasizes the importance of proper procedures, accurate documentation, and strict compliance standards in maintaining system reliability and trust.
Physiological factors can also affect breath test results. Mouth alcohol from belching, vomiting, or the presence of certain dental appliances can produce artificially elevated readings. Certain medical conditions, including acid reflux and diabetes, can affect the reliability of breath test measurements. An Indianapolis DUI Attorney who works with forensic toxicologists will identify any such factors that apply to your specific situation.
A Case Where the Defense Strategies Made All the Difference
I know an individual who was arrested for OWI in Indianapolis after a traffic stop on a weekend evening. The officer noted the smell of alcohol and observed what he characterized as unsteady gait. Field sobriety tests were administered, and a breath test showed a reading of 0.11%. He retained an Indianapolis DUI Attorney who reviewed the body camera footage of the field sobriety tests and identified that the walk-and-turn test had been administered on a surface that was not level and adequately lit as required by the NHTSA protocol, and that the one-leg stand test had not been properly demonstrated by the officer.
The attorney also requested the calibration records for the breath test device and discovered that the required quarterly calibration check had been performed six days later than the permitted interval. The combination of protocol violations in the field sobriety tests and the maintenance gap in the breath test device provided substantial grounds for challenging the reliability of the prosecution’s evidence. The case was ultimately resolved through a negotiated reduction to a lesser charge that avoided an OWI conviction. Defense strategy, not luck, determined the outcome.
The Rising BAC Defense
One of the most important and legally significant defenses in OWI cases is the rising BAC defense. Alcohol absorption is not instantaneous; after consuming alcohol, BAC continues to rise for a period of time as the alcohol is absorbed from the gastrointestinal tract. If a defendant consumed alcohol within a short period before driving and was still in the absorption phase, their BAC at the time of the chemical test may have been higher than their BAC at the time of driving.
Expert forensic toxicologists can calculate, based on the defendant’s weight, the amount consumed, the timing of consumption, and the time of the chemical test, whether the BAC was likely at or below the legal limit at the relevant time of driving. An experienced OWI defense attorney will evaluate whether this defense applies to your specific case.
Your Defense Begins the Moment You Call
Every day that passes after an OWI arrest without experienced legal representation is a day during which evidence may be lost, administrative deadlines may pass, and your options may narrow. An experienced Indianapolis DUI Attorney will act immediately: requesting the administrative hearing, gathering all available evidence, and beginning the strategic analysis that will determine the best defense approach. Do not wait to seek representation. The sooner you engage qualified legal counsel, the more tools your defense will have.
