Which test is typically preferred to assess blood alcohol content (BAC) in DWI cases?

The breath test is typically preferred to assess blood alcohol content (BAC) in DWI cases due to its immediacy and convenience. Breath tests are non-invasive and can be administered quickly at the roadside, providing immediate results. This allows law enforcement to make swift decisions regarding arrest and further processing of the DWI case.

Additionally, breath tests are often equipped with devices, such as breathalyzers, that are specifically calibrated to provide accurate BAC readings. These tests are also more practical in terms of time and logistics compared to blood tests, which require drawing blood, handling samples, and sending them to a lab for analysis.

While urine tests can also measure BAC, they tend to be less reliable than breath tests. They may not accurately reflect one's current impairment level, as alcohol can remain in the urine long after it has left the bloodstream. Field sobriety tests, on the other hand, do not measure BAC directly and are more subjective, relying on the officer's observations of the suspect's physical and cognitive performance. Therefore, the breath test is generally favored in DWI situations for its efficiency and direct measurement of blood alcohol content.