PBTs? SFSTs? When you’re pulled over on suspicion of driving under the influence (DUI) of alcohol, you’re going to get a crash course in some important acronyms.

You may be asked to submit to a preliminary breath test (PBT) or participate in one or more standardized field sobriety test (SFST) – and knowing your rights in this situation can be key to minimizing the fallout from the situation.

What are SFSTs?

These are a battery of tests used by law enforcement officers to assess a person’s level of impairment due to alcohol or drug use during traffic stops or suspected drunk driving incidents.

The three primary SFSTs commonly employed are:

  • The horizontal gaze nystagmus (HGN) test (aka the gaze test or the nystagmus test), which looks at involuntary eye movements that can become exaggerated when someone is intoxicated.
  • The walk-and-turn (WAT) test, a method of determining sobriety that looks at someone’s balance, coordination and ability to follow instructions, all of which can be affected by alcohol or drugs.
  • The one-legged stand (OLS) test, which is a sobriety test that also assesses someone’s ability to maintain their attention and balance.

SFSTs are not definitive proof of impairment, and they’re so subjective they aren’t even admissible in court. However, failing an SFST pretty much guarantees that you’ll be asked to submit to a breath or blood test to determine your blood alcohol concentration (BAC). It’s important to remember that you are not obligated to participate in these tests, and your refusal to do so will not subject you to any legal penalties.

What is a PBT test?

A PBT stands for preliminary breath test, and is a rapid method of gauging sobriety. In Pennsylvania, officers use a portable device that they carry for the purposes of estimating your blood alcohol content. If your reading is positive, they may then place you under arrest and obtain a second chemical test (breath or blood).

In many states, refusal to submit to BAC testing automatically puts a driver in violation of “implied consent laws” that tie agreeing to those tests as a condition for holding a driver’s license. In Pennslyvania, however, you are generally free to refuse a PBT pre-arrest without fear.

You’ll only incur additional penalties if you refuse to agree to post-arrest testing, at which point you can generally expect the police to obtain a warrant to force the issue. If you’ve just gotten a crash course in the harsh realities of a drunk driving charge, the wisest move you can make is to seek more information about your potential defenses. Speaking with a DUI attorney is a good place to start.