For the police to arrest and charge a driver for drunk driving, they need probable cause to prove that the driver is violating traffic laws. To do this, the police can gather evidence. For example, if the police notice an open alcohol bottle in a car, that may be enough evidence to warrant an arrest. More often than not, the police will begin investigating a driver by asking them questions, such as where they were or if they were drinking.
However, questions can only help the police so far. The police may use alternative methods to collect evidence. One way this is done is by asking drivers to perform field sobriety tests, which are a type of physical examination. If a field sobriety test is inconclusive, the police may ask drivers to submit a chemical test.
There are three kinds of chemical sobriety tests: breath, blood and urine. Each of these tests evaluates the amount of alcohol in the body, also called the blood alcohol content (BAC). These tests can have various results. Here’s what you should know about the accuracy of each test:
Comparing breath, blood and urine chemical tests
Of the three chemical sobriety tests, many people have heard of breath tests. Breath tests can be administered during traffic stops. The driver would be asked to blow into the tube of a small device. The device will then read the driver’s BAC result. Exceeding the legal BAC limit would mean the driver is violating traffic laws. Many people take breath tests because urine and blood tests require drivers to relocate to a police station or hospital. However, breath tests are not considered the most accurate.
Urine tests are often the least accurate and may only be used when a breath or blood test is not available. The most accurate chemical sobriety test is the blood test. However, lab testing errors can still result in incorrect evaluations.
If you believe the results are wrong or that your legal rights were violated during a traffic stop, then learning about your defense options could help you.