When it comes to DUI charges, some sources (usually found on internet forums) may tell you that refusing a breath test is a good strategy to thwart the prosecution’s case against you. After all, without the hard evidence of your blood alcohol concentration, how can they charge you with drunk driving?

The truth is that it’s not that simple. You can refuse to take a breath test, but prosecutors can use other evidence besides your BAC to build their case against you. Additionally, Illinois has unique laws when it comes to breath testing. So, before taking the advice of a random internet user, it’s best to understand exactly how Illinois DUI laws work.

Not all breath tests are equal

Illinois has two types of breath tests for DUI:

  1. A preliminary breath test (PBT), taken using a portable device at a traffic stop
  2. A more comprehensive breathalyzer test, usually administered down at the police station

Under Illinois DUI laws, you may refuse to take a PBT without incurring any penalties. Even if you take a PBT, the reading cannot be used as evidence in court. That’s good news, right?

Again, it’s not that simple.

What a preliminary breath test does

Like field sobriety tests, police officers use PBTs to establish probable cause for a DUI arrest. A police officer must have probable cause to arrest you for drunk driving. A PBT in effect protects this probable cause. If you blow over the legal limit (.08) on a PBT, it will be much harder to argue you weren’t drunk at the time you were pulled over.

As mentioned above, though, even if you refuse to submit to a PBT, you may still be arrested on suspicion of DUI based on other factors, like if you were weaving or speeding before being pulled over, or if you have slurred speech, bloodshot eyes or difficulty performing other field sobriety tests.

Refusing an official chemical test has consequences

After arrest, you will likely be asked to submit to further chemical testing down at the DuPage County police station. This usually means taking a breathalyzer test or giving blood or urine sample. Refusing any of these official tests will result in automatic and immediate penalties, including the suspension of your driving privileges for a year.

Also, the results of these tests are admissible in court. Your refusal could be admitted as evidence in a DUI trial. And, if you take the test and fail it, your license will be automatically suspended for up to six months.

So, the answer of whether you should submit to a breath test isn’t a simple “yes” or “no.” Every case will involve unique factors, not the least of which is your own understanding of Illinois’s DUI laws. Knowing your rights and the possible consequences of your actions will do much more to safeguard your freedom than simply going with your gut in the heat of traffic stop.