When is Chemical Testing Conducted in a DUI case?

When law enforcement investigates a drunk driving case, chemical testing is only one of the tools that they have to investigate the case. Law enforcement may conduct chemical testing both before and after an arrest. Chemical testing may occur at the side of the road, at the police station or at a hospital. Here’s when chemical testing is conducted in a DUI case:

After Field Sobriety Tests

A chemical test is an invasive procedure. It’s similar to a search by law enforcement. The law aims to protect members of the public from being subjected to unreasonable searches from law enforcement. The police shouldn’t begin to perform a chemical test until they’ve conducted field sobriety tests. The tests should give them an indication of whether there’s sufficient evidence to proceed with a chemical test.

In rare cases, law enforcement may not perform field sobriety tests. If a person has a physical condition that impacts their balance or if the surface they’re on is very uneven, a field sobriety test may be unreliable. However, in the vast majority of cases, the officer decides whether to proceed with chemical testing in a DUI case only after doing field sobriety tests.

At the Side of the Road

Law enforcement may administer a preliminary chemical test at the side of the road. This test is called a portable breath test or PBT. A PBT is a device that measures the alcohol content in the air that a person breathes. A PBT is a small, portable device that an officer can keep with them in their patrol car. When they investigate a drunk driving offense, they can take out the PBT instrument to perform the test.

Law enforcement conducts this test at the side of the road. Usually, the PBT test comes before they make an arrest. The purpose of the PBT is to determine if there’s probable cause to make an arrest. The PBT test flashes a result that indicates the driver’s bodily alcohol content.

The PBT test that police administer at the side of the road isn’t as reliable as the breathalyzer that they may give you at the police station. A PBT test is more prone to variations in measurement that may make the test inaccurate. The police should rely on their entire investigation when they make the decision of whether or not to arrest someone and take them to the station for additional testing.

A PBT test can measure only alcohol. If the police suspect you of marijuana use or use of another drug, they may not administer a PBT. The chemical testing that the police choose to administer in your case may vary depending on the nature of the investigation.

After you Hear your Chemical Test Rights

If the police make an arrest in your case, they must inform you of your chemical test rights. Even though the law presumes that all drivers consent to take a chemical test, the law enforcement officer must still inform you of your chemical test rights. They must warn you that if you refuse to take the test, the State of Illinois may suspend your operator’s license. The law enforcement officer typically does not proceed with a chemical test until after they’ve given you this warning. If they fail to give you the proper warning, the chemical test may not come into evidence against you if your case goes to trial.

At the Police Station

Most people who are arrested for drunk driving take a breath test. The breath test most often occurs at the police station. Almost every police station is equipped with one or more instruments for formal breath testing. The police have to follow the rules for performing a chemical test. The police typically administer the breath test after they arrest you and drive you to the police station.

At a Hospital

In cases where the police don’t administer a breath test, they may conduct a blood test administered by a medical professional. A blood test in a DUI case is typically conducted after a person is under arrest. The police may have you take a blood test if they suspect that you’re under the influence of drugs instead of alcohol. They may also administer a blood test after you refuse to take a breath test. In that case, the police may have to obtain a warrant to draw your blood if you don’t consent to the blood test.

Evaluating the Chemical Testing in your Case

The police may only administer chemical testing in a DUI case at the appropriate time. They should have reasonable grounds to suspect you of DUI before they ever conduct a chemical test. Formal testing should occur only after a formal arrest and after following strict procedures. Your attorney can help you determine if law enforcement conducted chemical testing appropriately in your case.

FAQ: When Is Chemical Testing Conducted in a DUI Case?

1) What is chemical testing in a DUI case?

Chemical testing is a tool law enforcement uses to investigate suspected drunk driving. It may be conducted before or after an arrest and can happen at the roadside, police station, or hospital.

2) When do police usually perform chemical testing during a DUI investigation?

Chemical testing is often conducted:

• After field sobriety tests

• At the side of the road (portable breath test)

• After the driver is informed of chemical test rights

• At the police station (breathalyzer)

• At a hospital (blood test)

3) Do police have to do field sobriety tests before chemical testing?

In most cases, yes. The content explains that chemical testing is considered invasive and similar to a search, so officers typically conduct field sobriety tests first to determine if there is enough evidence to proceed with chemical testing.

4) Are there times when field sobriety tests are not performed?

Yes. Field sobriety tests may be skipped in rare cases, such as when:

• The driver has a physical condition affecting balance

• The ground surface is uneven and would make the test unreliable

5) What is a Portable Breath Test (PBT)?

A Portable Breath Test (PBT) is a small handheld device used by officers at the roadside to measure alcohol in a person’s breath. It helps determine whether there is probable cause to make an arrest.

6) Is a roadside PBT the same as the breathalyzer at the police station?

No. The content explains that a PBT is not as reliable as the breathalyzer used at the police station. PBT devices are more prone to measurement variations that may affect accuracy.

7) What is the purpose of a PBT during a DUI stop?

The purpose of a PBT is to help officers decide whether there is probable cause to arrest a driver and take them for further testing.

8) Can a PBT detect drugs like marijuana?

No. A PBT measures alcohol only. If police suspect marijuana or other drug impairment, they may use different testing methods.

9) When do police read chemical test rights?

After an arrest, officers must inform the driver of their chemical test rights. They must also warn that refusing the test can lead to the state suspending the driver’s license.

10) What happens if police do not properly warn you about chemical test rights?

If law enforcement fails to give the proper warning before the test, the chemical test results may not be allowed into evidence if the case goes to trial.

11) Where does formal breath testing usually happen?

Formal breath testing most commonly happens at the police station after arrest. Most police stations have equipment for official breath testing, and officers must follow strict procedures when administering the test.

12) When is a blood test used in a DUI case?

A blood test may be used when:

• Police suspect drug impairment instead of alcohol

• A breath test is not administered

• The driver refuses a breath test (and police seek another method)

13) Do police need a warrant for a DUI blood test?

Sometimes. The content explains that if a driver does not consent to a blood test, police may need to obtain a warrant to draw blood.

14) Can chemical testing be challenged in a DUI case?

Yes. Chemical testing must be done at the proper time and under strict procedures. An attorney can review whether law enforcement had reasonable grounds and whether testing was conducted appropriately.