When charged with driving under the influence (DUI), conviction requires proof beyond a reasonable doubt.
In some cases, charges rest entirely on a host of evidence collected by the prosecution in order to convict. A DUI case, and its subsequent conviction and sentencing, depends on the validity and strength of this evidence.
Common forms of evidence
A DUI conviction may result in jail time, fines, driving restrictions and other criminal penalties. The severity of punishment is often determined by the evidence to support the severity of the case.
The prosecution must produce proof of intoxication while operating a vehicle, which may be in the form of:
- Field sobriety tests
- Breathalyzer results
- Blood alcohol content test results
- Physical evidence, including open containers or paraphernalia in the vehicle
- Traffic violations or related crimes
- Witness or officer testimony
These forms of evidence must prove that the driver was certainly operating the vehicle while under the influence of drugs or alcohol, demonstrating a blood alcohol level above .08% or evidence of impairment.
In some cases, the evidence in a DUI case is eligible for dispute. Field sobriety tests and breathalyzer results are often compromised by additional factors, including human error, confounding variables or improper administration of the tests.
As well, the police officer must prove that a traffic stop was under reasonable suspicion. Unlawful traffic stops may invalidate any evidence obtained during the detainment.
Prosecutors must also prove the defendant was driving and intoxicated at the time of the stop, which may be subjective or difficult to determine in some cases. Failure to do so can weaken a DUI case or compromise charges entirely.