If a motorist is suspected of Driving Under the Influence (DUI),  law enforcement will request breath and or blood tests. There are two types of breath tests that must be distinguished.

Before police can make an arrest for DUI, they must have probable cause to believe the driver has committed the offense.  In other words, they must gather a sufficient amount of evidence to create  a “substantial chance” or “fair probability” of criminal activity. (Illinois v. Gates, 462 U.S. 213 (1983))

This evidence gathering depends in part upon the officer’s observations of the driver’s actions and conduct. This would include the driver’s compliance with safe driving habits and obedience to traffic laws, his or her reaction to the officer’s commands to stop and their maneuvers while pulling over.

After approaching the driver, the officer would note the driver’s physical appearance and actions (bloodshot eyes, odor of alcohol, slurred speech), ability to follow instructions and understanding of time and place.  The officer would also be cognizant of the driver’s movements upon leaving the vehicle (staggering, unsteady balance,  difficulty getting out of the vehicle).

Once the driver has come back to the squad car-typically within range of a dash cam-the investigating officer will have the driver perform standardized field sobriety tests. First up would be the horizontal gaze nystagumus. In this test, the officer moves a pencil in front of the driver’s eyes looking for certain reactions from his pupils that allegedly are “clues” to intoxication.

The next test on which the driver will be scored is the walk-and-turn.  Nine steps down, turn around, nine steps back.  However, there are many maneuvers within that walk.  Heel to toe, arms down, watching your feet, counting each step aloud, staying on the invisible line, a proper turn.

The last field sobriety test will be the one-legged stand. Stand on one leg, lift the other leg six inches off the ground, watch that leg, don’t use your arms for balance and count to 30.

Following all of these tests, the driver will be asked to take what is known as a Preliminary Breath Test (PBT).  This test employs a device that is not certified for accuracy and that is administered by someone with no particular training in its use.

The results of the PBT cannot be used to prove a person’s blood alcohol level (BAL) but the officer may consider it as part of his probable cause determination. (625 ILCS 5/11-501.5)  There is no criminal or driver’s license penalty for not taking the PBT.

Once arrested for DUI,  the driver will be asked to take a “chemical test” which means either a blood test or a breath test using a certified machine operated by a technician certified to use the machine. Unlike some other states, refusing to take a chemical test is not a crime in Illinois. However, a refusal does bring enhanced driver’s license penalties.

Someone facing a DUI fewer than five years after an earlier DUI and who refuses will be suspended for three years whereas one who submits to testing receives a suspension of one year upon registering above the legal limit of .08. Someone with no DUI in the last five years will be suspended for a year in a refusal situation and six months if registering above the legal limit of .08.

That being the case, how can there be a no refusal weekend?  A blood draw done for the purpose of collecting evidence in a criminal prosecution is a search under the Fourth Amendment. Subject to a (growing) list of exceptions, a search requires that the police obtain a warrant from a neutral magistrate.

Police have argued in the past that the emergency exception to the search warrant requirement should apply to DUI because by the time the police obtain a warrant, the alcohol in the blood will have gone down and along with it, evidence of a crime. However, the Unites States Supreme Court, in McNeely v. Missouri, held that the police must obtain a warrant.

Police will not routinely obtain a warrant in a standard DUI arrest because of the time and trouble of doing so, as well as the time and expense of drawing and analyzing the blood. However, jurisdictions do from time to time have “no refusal weekends” in which they make a policy decision in advance to obtain a search warrant for anyone who refuses testing.

Anyone who refuses to give a blood draw after the police obtain a warrant may be held in contempt of court, possibly be charged with obstruction of justice and maybe even have blood forcibly drawn.