What is the main function of a breathalyzer in a DUI investigation?

The main function of a breathalyzer in a DUI investigation is to measure a person's blood alcohol concentration (BAC). This device analyzes the chemical composition of a person's breath to provide an estimate of the amount of alcohol present in their bloodstream. The BAC is a critical indicator used by law enforcement to determine impairment due to alcohol consumption, which is crucial in assessing the legality of an individual's ability to operate a vehicle safely.

Breathalyzers are designed specifically to quantify alcohol levels in a quick and non-invasive manner, which is essential during roadside checks or traffic stops. Understanding an individual's BAC helps officers make informed decisions about arrests and potential charges for DUI offenses. This measurable data can later be used in court to establish whether a driver was legally over the limit, which is typically set at 0.08% BAC in many jurisdictions for operating a vehicle.

In contrast, other options such as identifying the type of alcohol consumed or measuring blood pressure are not functions of a breathalyzer. The device doesn't provide insights into a person's overall risk level on the road or his or her physical health metrics beyond alcohol impairment.