DUI Probable Cause: What Are The Police Looking For?


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DUI Probable Cause: What Are The Police Looking For?

DUI Probable Cause:  What Are The Police Looking For?

DUI Probable Cause - What are the police looking for?

It’s a basic constitutional requirement in any criminal case that police support any arrest with probable cause. With DUI Probable Cause – What are the police looking for?

All probable case legal issues are analyzed through the law of search and seizure, which starts with the federal Constitution.  The U.S. Constitution’s 4th Amendment states as follows:  “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.’”

The police may interfere with an individual’s Fourth Amendment interests without a warrant if the intrusion is only minimal and is justified by law enforcement purposes. (Michigan State Police Dept v. Sitz, 496 U.S. 444, 450 (’90); Terry v. Ohio, 392 U.S. 1, 20 (’68)).   The case of Maryland v. Brady, 527 U.S. 465 (1999) , also holds along with a long line of other cases, that a warrant is not needed for vehicle searches, since a lessened expectation of privacy exists as to vehicles.

Article 1, section 13 of the California Constitution and applicable case law, requires that police establish probable cause, to conduct an arrest for a crime.  In most cases, the officer will identify and describe some particular violation of the California Penal of Vehicle code, such as speeding, accelerating rapidly, weaving, or driving without headlights on. There are other situations where officers respond to an accident, or find someone stranded by the side of the road, which doesn’t involve police observing driving. But the typical situation is where a person is stopped for alleged erratic driving as officially recognized by The National Highway Traffic Safety Administration (NHTSA).

NHTSA (The National Highway Traffic Safety Administration), in their manual for detecting DUI written for training all officers in the USA), says:

 “Driving is a complex task involving a number of subtasks, many of which occur simultaneously, These include: steering, controlling the accelerator, signaling, controlling the brake pedal, operating the clutch, operating the gearshift, observing other traffic, observing signal lights, stop signs & other traffic control devices, and making decisions (weather to stop, turn speed up, slow down). Safe driving demands the ability to divide attention among these various tasks. Divided attention simply means the ability to concentrate on two or more things at the same time.

Under the influence of alcohol and/or other drugs a driver’s ability to divided attention is impaired. As a result, the impaired driver tends to concentrate on only the most important or critical parts of driving and to disregard the less important parts, often creating unexpected or dangerous situations for other drivers (P.V-9, NHTSA SFST Student Manual, 2002).

Additionally, Officers typically indicate the presence of several factors, all of which they state give cause to investigate further for DUI. These included:

  • Red, bloodshot, watery eyes;
  • Odor of alcoholic beverage;
  • Unsteady Gait; and
  • Slurred Speech.

Odor of Alcohol

Regarding an odor of alcohol on someone’s breath it would be reasonable to believe, based on previous studies, that it would be extremely difficult to correlate the odor of breath alcohol to a particular level of intoxication. 

In testing breath in the field, in 1998, the Southern California Research Institute (SCRI) in cooperation with the Insurance Institute for Highway Safety conducted a study entitled “Police officer’s detection of breath odors from alcohol ingestion” authored by Herbert Moskowitz, Marceline Burns, and Susan Ferguson.

The end results of this research indicated that “it was demonstrated that officer’s were able to derive only limited information from alcohol odor“. These findings are consistent with the Widmark (1932) police station study and the Compton (1985) open air roadside studies. Both previous studies found small likelihood of detecting breath alcohol odors for BAC’s below 0.08 and 0.10% and detection failures even below 0.10%”. As with the Widmark and the Compton studies on breath alcohol odor, the SCRI study also indicated that the officer’s were unable to consistently classify odor of alcohol to intoxication levels. This was especially evident at 0.08% BAC’s and lower.

Bloodshot and Watery Eyes

Horizontal Gaze Nystagmus (HGN) Field Sobriety Test

Police Officers also often report that they observe eyes to be bloodshot and watery.

There are several reasons and irritants that could cause one’s eyes to be bloodshot and watery.  One reason for this could be that many people have allergies to dusts and different pollen in the air. Another reason that the eyes could be this way is if a person wears contact lenses and they have dried out. As a result of the eye having no moisture to relieve the discomfort of the dryness the eye becomes irritated and red.

In addition, redness of the eyes can be caused simply based on the environment the person has been in. If a person is in a location where public smoking is allowed, redness can be caused due to a wide variety of different contaminates in the air. Smoke, dust and other airborne contaminates can get into the eyes of a person and cause irritation and redness.  Lack of sleep also may cause the eyes to redden. It is quite possible that many drivers are also tired and due to ocular fatigue displayed some irritation.

Regarding watery eyes, everyone always has watery looking eyes. This is due to the moisture level in the eye itself and the fact that the eyes continually blink covering the eyeball with a clear sheen of moisture to keep the eye from drying out. The only time the eye would not have a watery look is when an individual has a serious eye disorder such as blindness, glaucoma, cataracts etc. This watery look can also be exaggerated as a result of a light shining in ones eyes because the moisture on the eyes surface acts as a mirror of sorts and the light will have a tendency to glare off of the surface of the eye.

Additionally, there would be no way for police officers to know for sure whether or not a driver has slurred speech due to alcohol, since they presumably had never spoken to the driver before the stop.

Miranda Rights/Warnings

The Fifth Amendment of the U.S. Constitution prevents you from being a witness in a case against you, and provides your right to remain silent.  Often, a person arrested for DUI was not read Miranda rights before questioning.  Should a case like that go to trial, the driver would have the right to bring a motion to suppress your statements and admissions as to drinking.  Unless the court believes that the entire questioning was consensual, your admissions should be suppressed.  However, in a DUI case, it’s not the confessions that are the strongest evidence – it’s the breath or blood test, which are not suppressed.

DUI Probable Cause – What are the police looking for?

So DUI Probable Cause – What are the police looking for? All of the above.  Traffic violations, an indication that the person had consumed alcohol (through an admission of alcohol consumption, or unsteady balance, red, watery eyes, and an odor of alcohol.

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