Analysis of a blood sample is potentially the most accurate, since it shows the presence of both alcohol and drugs. The least accurate and least reliable, by far, however, is urinalysis. There are a number of potential defenses that can be raised in a given drunk driving case. This may be difficult if, as in the case of accidents, there are no witnesses to you being the driver of the vehicle. Most drivers quickly admit they were driving, although they had the right to remain silent.
Sobriety roadblocks present particularly complex issues.
Incriminating statements may be suppressed if warnings were not given at the appropriate time. Implied consent warnings. Witnesses can testify that you appeared to be sober. There exists a wide range of potential problems with blood, breath, or urine testing. Radio frequency interference can result in inaccurate readings.