Specific DWI Trial Recommendations for police officers
1. Never give the numerical PBT reading of the defendant when asked by the
prosecutor. However, if the defense attorney asks you for the NUMERICAL
reading, give it to him/her. The prohibition of PBT results of a defendant do not
apply to witnesses, such as passengers in the car.
2. Discuss with the prosecutor, pre-trial, whether or not to demonstrate how you
conducted field sobriety tests. Be certain that you can do in court all the tests you
asked the defendant to perform at the time of the arrest. If you cannot do them, the
jury will not expect that the defendant could have done them properly.
3. Know the reasons for giving field sobriety tests:
• They are divided attention tests, designed to detect when a person is impaired
by alcohol and/or drugs.
• They provide evidence of impairment in cases where the defendant refuses to
take a chemical test under implied consent.
• They prevent an arbitrary decision to arrest, and allow an officer to articulate the
reasons for concluding that a driver was DWI.
4. If you testify to the accuracy of the field sobriety tests, make sure you know the
studies, percentages, and their significance. Considered independently, the
Nystagmus test was 88% accurate, the Walk and Turn, 79% accurate, and the One
Leg Stand, 83% accurate in identifying subjects whose BAC were .08 or more.
5. Remember, you should not testify that the defendant passed or failed the SFSTs.
The tests are not scored “pass” or “fail.” You should testify if the defendant
completed the tests as instructed. These tests simply identify impairment.
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SAMPLE DWI INCIDENT REPORT
Defendant: Eryn Greenfield
Date of Birth: 10/03/XX
Date of Arrest: XX-XX-XX
Time of Arrest: 9:20 pm
CA - D.L. #: CA 1234567
On XX-XX-XX at approximately 9:00 p.m., I was patrolling westbound on Reed Avenue
at the intersection with Interstate 80 (fully marked CHP patrol vehicle #904534). I was
stopped at the intersection preparing to make a left turn onto eastbound I-80. I
observed a yellow Volkswagon (S/V) traveling down the eastbound I 80 exit ramp
approaching the intersection with Reed Avenue. I noticed the S/V traveling with no
headlights. I also noticed that the front right parking light was not working correctly.
Furthermore, I noticed the right tires of the S/V travel over the solid white fog line on the
exit ramp by approximately 2 feet. The S/V made a brief stop at the intersection, then
made a right turn onto eastbound Reed Avenue without using a turn signal. I made a U
turn and followed the S/V. The S/V then made a wide right turn from Reed Avenue onto
southbound Riverpoint Drive without using a turn signal. An enforcement stop was
initiated at which point the S/V began to pull to the right. At the point the right front tire
of the S/V rubbed up onto the raised concrete curb that paralleled the roadway.
Observations After The Stop:
I approached the S/V on the passenger side and made contact with the driver
(convertible top down). I immediately noticed that the driver had red, bloodshot, watery
eyes. I advised her of the reason for the stop and asked if her vehicle had any
mechanical problems. She stated, “no.” I requested her driver’s license, registration,
and insurance. The driver removed a stack of cards from her wallet, which was located
in her purse on right front passenger seat. She began sifting through the stack of cards.
I observed her clearly pass by her license and continue searching through the cards.
Unable to locate her license on the first attempt, she started over at the top and located
the license on the second attempt. She was identified as Eryn Greenfield by California
driver’s license (#CA1234567). After handing me the license, she did not make an
attempt to retrieve the other documents I had requested. I asked her again for the
registration and insurance cards. She then retrieved them out of the glove
compartment. I asked her how much alcohol she had consumed and she stated “a
couple of beers about an hour ago.” I asked her what size and type of beer and she
replied with 12oz. bottles of Heineken. I asked her if she felt the effects of the drinks
and she stated, “No, I feel fine.” As she spoke, I noticed that her speech was slurred. I
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asked her to exit the vehicle and step to the side walk so I could administer several field
sobriety tests to her (see field sobriety test section). As she exited the vehicle, she
stepped around the front as instructed, then stumbled on the raised curb. I asked her
several pre-field sobriety test questions of which she answered accordingly (see page 2
of face page). As I communicated with her, I smelled an odor of alcoholic beverage
emitting from her breath.
Field Sobriety Tests:
This evaluation was performed on Riverpoint Drive, just south of Reed Avenue. The
evaluation surface was smooth concrete. Lighting conditions consisted of patrol vehicle
headlights, spotlights, overhead lights, streetlight, and my flashlight. No surface defects
were noted or claimed. It was noticeably windy.
Horizontal Gaze Nystagmus (explained):
I observed lack of smooth pursuit, distinct and sustained nystagmus at maximum
deviation, and an onset of nystagmus prior to 45 degrees in both of Greenfield’s eyes.
Greenfield was swaying forward and backward significantly during the test. At least 3
inches in both directions.
Walk and Turn (explained and demonstrated):
Instruction Stage: Lost balance (feet broke apart)
Walking Stage (1st Nine): Walked 10 steps (counted 10).
Raised left arm over 6 inches away from body to assist with balance on one occasion
(at steps 4 - 5).
Walking Stage (2nd Nine): Walked 10 steps (counted 9).
Raised left arm over 6 inches away from body to assist with balance on tow occasions
(at steps 6 - 7).
Turn: Lost balance during turn and did not turn as instructed. Greenfield only took one
step during the turn instead of several small steps as instructed.
One Leg Stand (explained and demonstrated):
While explaining the test, Greenfield started before being told to begin. Greenfield
raised her left leg and began counting. She put her foot down on counts 1006 and
1009. As she was counting, she skipped 1017 (counting from 1016 to 1018). Used
right arm for balance (6+ inches from body) and was swaying while balancing. She
counted to 1019 after 30 seconds.
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Based on the following information, I formed the opinion that Greenfield was driving
under the influence:
• Driving at night with no headlights.
• Driving to the right of the solid white fog line on exit ramp.
• Making wide right turn from eastbound Reed Avenue to southbound Riverpoint
Drive without using a turn signal.
• Right tire rubbing against raised concrete curb after stop was initiated.
• I observed divided attention problems while retrieving her license/registration and
• Her red, bloodshot, watery eyes and slurred speech.
• Her admissions to consuming alcoholic beverages.
• Stumbling over curb after exiting the vehicle.
• Odor of alcoholic beverage emitting from her breath.
• I observed signs of impairment as she performed the standardized field sobriety
I arrested Greenfield for driving under the influence of an alcoholic beverage at 9:20
p.m. Greenfield was given the proper chemical testing advisement. She chose a breath
test and was transported to the breath testing facility. She provided two breath samples
of 0.08 and 0.08 at 9:50 p.m. and 9:52 p.m. She was then booked along with her
I recommend a copy of this report be forwarded to the district attorney’s office for review
and prosecution of Greenfield for driving under the influence and driving with a blood
alcohol concentration at or above the legal state limit.
Greenfield’s vehicle was stored by Reliable Towing.
HS 178 R5/13 1 of 5 Source: DWI Detection and
March 2013 Edition