In a DUI stop, officers may ask you to perform tests and provide a breath sample. The rules on what is voluntary and what carries penalties differ.
Field sobriety tests
Roadside tests such as walking a line or following a pen are often voluntary and are subjective. They are designed to gather evidence for arrest. Many lawyers advise politely declining, but consequences vary and officers may rely on other observations.
Preliminary breath tests
A handheld roadside breath test is often optional for drivers 21 or older but may be mandatory for drivers under 21, commercial drivers and drivers on probation in some states.
Chemical tests after arrest
Every state has implied consent laws, meaning that by driving you agree to take a breath, blood or urine test after a lawful arrest. Refusing can lead to automatic license suspension and be used against you in court, and some states may seek a warrant for blood.
What to do
- Stay polite and do not argue.
- Provide license, registration and insurance.
- Say that you want to speak with a lawyer.
- Ask about the consequences of refusal under your state's law.
- Act quickly on the administrative license deadline. See our DUI guide.
Frequently asked questions
Can I be arrested without a breath test?
Yes, based on officer observations and other evidence.
Are breathalyzers always accurate?
No. Calibration, medical conditions and procedures can affect results.