Tuesday, April 21, 2009

DWI - Typical Investigation and Arrest

Following are common procedures when a law enforcement officer has reason to suspect a driver is intoxicated.

Reasonable Suspicion to stop

There are several situations in which the officer will come into contact with a driver, some examples are:
- The driver has been involved in an automobile accident, the officer has responded to the scene and is conducting an investigation.
- The driver has been stopped at a sobriety checkpoint (also known as roadblocks).
- The police have received a report, possibly from an anonymous citizen, that a described car has been driving erratically. The officer should verify the erratic driving before pulling the driver over. In some cases, the driver will no longer be in the vehicle.
- The officer on patrol has observed erratic, suspicious driving, or a series of traffic infractions indicating the possibility that the driver may be impaired. This is by far the most common reason for stopping a suspect.
A police officer has stopped a vehicle for a lesser traffic offense, notices the signs of intoxication, and begins the DWI investigation.

The following list of DWI symptoms, from a publication issued by the National Highway Traffic Safety Administration (DOT HS-805-711) is widely used in training officers to detect drunk drivers. After each symptom is a percentage figure which, according to NHTSA, indicates the statistical chances through research, that a driver is over the legal limit.

f the officer observes enough to have a reasonable suspicion to legally justify a further detention and investigation, he will ask the driver to step out of the vehicle.

Reasonable suspicion requires less evidence than probable cause, but more than a mere hunch. A rule of thumb is that reasonable suspicion requires 25 % proof, and probable cause requires more than 50 % statistical chance. Therefore, if there is probable cause for arrest for DWI, as suggested by the research and examples used above, then there is reasonable suspicion to stop a driver.


The officer will typically approach the driver's window and ask some preliminary questions. During this phase of the stop the officer will note if they detect any of the following indicators of intoxication:

- odor of an alcoholic beverage on the driver's breath or in the car generally
slurred speech in response to the questioning
- watery, blood shot, and/or reddish eyes
- flushed face
- droopy eyelids
- difficulty in understanding and responding intelligently to question
- fumbling with his or her driver's license and registration
- the plain-view presence of containers of alcoholic beverages in the vehicle
- admission of consumption of alcoholic beverage

If the officer observes enough to have a reasonable suspicion to legally justify a further detention and investigation, he will ask the driver to step out of the vehicle. In some states (Texas and Louisiana, for example), if the officer has reasonable suspicion or probable cause to make the stop, the driver can be ordered out of the vehicle at any time, not just during a DWI investigation.

Field sobriety tests

The officer will administer one or more field sobriety tests (FSTs). FSTs are "divided attention tests" that theoretically test the suspect's ability to perform the type of mental and physical multitasking that is required to operate an automobile. The most commonly administered FSTs include:
- horizontal gaze nystagmus test, which involves following an object with the eyes (such as a pen) to determine characteristic eye movement reaction. A sober person should be able to smoothly track the object with their eyes. In an intoxicated individual the eyes will jerk as they follow the object
- walk-and-turn (heel-to-toe in a straight line)
- one-leg-stand
- modified-position-of-attention (feet together, head back, eyes closed for thirty seconds; also known as the Romberg test)
- finger-to-nose (tip head back, eyes closed, touch the tip of nose with tip of index finger)
- recite all or part of the alphabet (a common myth is that the alphabet must be recited backwards, however, this is never done during an FST, as many sober people are unable to do this)
- touch each finger of hand to thumb counting with each touch (1, 2, 3, 4, 4, 3, 2, 1)
- count backwards from a number such as 30 or 100.
- breathe into a "portable or preliminary breath tester" or PBT.

Although most law enforcement agencies continue to use a variety of these FSTs, increasingly a 3-test battery of standardized field sobriety tests (SFSTs) is being adopted. These tests are recommended by the National Highway Traffic Safety Administration (NHTSA) after studies indicated other FSTs were relatively unreliable. The NHTSA-approved battery of tests consists of the horizontal gaze nystagmus test, the walk-and-turn test, and the one-leg-stand. In some states, such as Ohio, only the standardized tests will be admitted into evidence, provided they were administered and objectively scored "in substantial compliance" with NHTSA standards (ORC 4511.19(D)(4)(b)).

FSTs are more effective at determining the level of impairment than they are at estimating the driver's blood alcohol concentration (BAC). However, studies question whether the tests increase the officer's ability to judge either. In 1991, Dr. Spurgeon Cole of Clemson University conducted a study on the accuracy of FSTs. His staff videotaped individuals performing six common field sobriety tests, then showed the tapes to 14 police officers and asked them to decide whether the suspects had "had too much to drink and drive". The blood-alcohol concentration of each of the 21 DWI subjects was .00, unknown to the officers. The result: the officers gave their opinion that 46% of these innocent people were too drunk to be able drive. This study showed the possible inaccuracy of FSTs.

An increasingly used field sobriety test involves having the suspect breathe into a small, handheld breath testing device. Called variously a PAS ("preliminary alcohol screening") or PBT ("preliminary breath test"), the units are small, inexpensive versions of their larger, more sophisticated instruments at the police stations, the EBTs ("evidentiary breath test"). Whereas the EBTs usually employ infrared spectroscopy, the PAS units use a relatively simple electrochemical (fuel cell) technology. Their purpose, along with other FSTs, is to assist the officer in determining probable cause for arrest. Although because of their relative inaccuracy they were never intended to be used in court for proving actual blood-alcohol concentration, some courts have begun to admit them as evidence of BAC.

Probable cause to arrest

If the officer has sufficient probable cause that the suspect has been driving under the influence of alcohol, he will make the arrest, handcuff the suspect and transport him to the police station. En route, the officer may advise him of his Miranda rights and his legal implied consent obligation to submit to an evidentiary chemical test of blood, breath or possibly urine.

Laws relating to what exactly constitutes probable cause vary from state to state. In California it is a refutable presumption that a person with a BAC of .08 or higher is driving under the influence. However, section 23610(a)(2) of the California Vehicle Code states that driving with a BAC between .05 and .08 "shall not give rise to any presumption that the person was or was not under the influence of an alcoholic beverage."

Chemical test

At the police station, the arrestee will be offered a chemical test of breath, blood or, much less frequently, urine. Breath test results are usually available immediately; urine and blood samples are sent to a lab for later analysis to determine the BAC or possible presence of drugs.

If the arrestee refuses to submit to chemical testing, he will usually be booked for driving under the influence, there will be no evidence for filing the second charge of driving with .08% blood alcohol content. In some cases the arrestee may be charged with DWI even after passing a breathalyzer test if he or she refuses also to take subsequent urine or blood tests. However, the refusal will carry increased penalties on the driving under the influence charge (typically a longer license suspension and/or an increased jail sentence), and the act of refusing may be admissible in court as evidence of "consciousness of guilt". In some states, refusal to submit to a chemical test can result in an automatic suspension of driving privileges, regardless of whether the suspect is convicted of DWI. In an increasing number of jurisdictions, if the suspect refuses to take a chemical test the police in some states may restrain the individual and forcefully withdraw blood. This is particularly common in situations involving an accident with injury or death. In some jurisdictions this may require obtaining a warrant from a judge. Some commentators, such as Brown University's Jacob Appel, have criticized the role of medical personnel in this process. According to Appel, "If physicians acquiesce today in the removal of a resistant patient's blood, soon they may be called upon to pump the contents of an unwilling patient's stomach or even to perform involuntary surgery to retrieve an evidentiary bullet."

While chemical tests are used to determine the driver's BAC, they do not determine the driver's level of impairment. However, state laws usually provide for a rebuttable legal presumption of intoxication at blood alcohol levels of .08 or higher.

The accuracy of breath, blood and urine testing is a subject of some dispute, with various scientific studies indicating unreliable results (see breathalyzer). In any case, breath and urine tests can only estimate the BAC at the time the test is taken, which can be different than when the vehicle was actually operated.

Booking and charging

If it is determined after arrest that the person's blood alcohol concentration is not at or above the legal limit of .08, they will probably be released without any charges. One may, however, still be charged with driving under the influence of alcohol on the basis of driving symptoms, observed impairment, admissions and/or performance on the field sobriety tests. And if there is suspicion of drug usage, a blood or urine test is likely, or at least the testimony of a specially-trained officer called a Drug Recognition Expert (DRE). Assuming sufficient evidence of impaired driving from drugs, the arrestee may face charges of driving under the influence of drugs or the combined influence of alcohol and drugs.

Most of the time, the driver will either be kept in a holding cell (sometimes referred to as the "drunk tank") until he is deemed sober enough to be released on bail or on his "own recognizance" ("O.R."). A date to appear in court for an arraignment will be given to him. If he cannot make bail or is not granted O.R., he will be kept in jail to wait for the arraignment on remand.
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Driving While Intoxicated

Driving while intoxicated is the act of operating and/or driving a motor vehicle while under the influence of alcohol and/or drugs to the degree that mental and motor skills are impaired. It is illegal in all jurisdictions within the U.S. The specific criminal offense is usually called driving under the influence (of alcohol and/or other drugs, DUI), and in some states driving while intoxicated (DWI), operating while impaired (OWI), or operating a vehicle under the influence (OVI). Such laws may also apply to boating or piloting aircraft.

In the United States the National Highway Traffic Safety Administration (NHTSA) estimates that 17,941 people died in 2006 in "alcohol-related" collisions, representing 40 percent of total traffic deaths in the US. Over 500,000 people were injured in alcohol-related accidents in the US in 2003. NHTSA defines fatal collisions as "alcohol-related" if they believe the driver, a passenger, or an occupant of the vehicle (such as a pedestrian or pedalcyclist) had a blood alcohol content (BAC) of 0.01 or greater. NHTSA defines nonfatal collisions as "alcohol-related" if the accident report indicates evidence of alcohol present. NHTSA specifically notes that "alcohol-related" does not necessarily mean a driver or nonoccupant was tested for alcohol and that the term does not indicate a collision or fatality was caused by the presence of alcohol. On average, about 60 percent of the BAC values are missing or unknown. To analyze what they believe is the complete data, statisticians simulate BAC information. Drivers with a BAC of 0.10 are 6 to 12 times more likely to get into a fatal crash or injury then drivers with no alcohol.