DWI Detection and Standardized Field Sobriety Testing Session 5 – Phase One: Vehicle in Motion Visual Detection of Driving While Intoxicated

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

Visual Detection of Driving While

Intoxicated

5-8

The common effects of alcohol on the driver's mental and physical faculties lead to

predictable driving violations and vehicle operating characteristics. The National

Highway Traffic Safety Administration (NHTSA) sponsored research to identify the most

common and reliable initial indicators of DWI. This research identified 24 cues, each

with an associated high probability that the driver exhibiting the cue is impaired. These

cues and their associated probabilities are described in the NHTSA publication, The

Visual Detection of DWI Motorists.

They also are discussed in Visual Detection of Driving While Intoxicated, a video

sponsored by NHTSA to assist law enforcement officers to recognize DWI detection

cues.

(ANACAPA Sciences, DOT HS 808 654, 1997.)

The National Highway Traffic Safety Administration sponsored research to identify the

most common and reliable initial indicators of DWI.

Research identified 100 cues, each providing a high probability indication that the driver

is under the influence.

The list was reduced to 24 cues during three field studies involving hundreds of officers

and more than 12,000 enforcement stops.

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 6 of 19

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

• Problems in maintaining proper lane

position

• Speed and braking problems

• Vigilance problems

• Judgment problems

Most Common and Reliable Initial

Indicators of DWI

5-9

The driving behaviors are presented in four categories:

• Problems in maintaining proper lane position

• Speed and braking problems

• Vigilance problems

• Judgment problems

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 7 of 19

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

• Weaving

• Weaving across lane line

• Drifting

• Straddling a lane line

• Swerving

• Almost striking object or vehicle

• Turning with a wide radius

Problems Maintaining

Proper Lane Position

5-10

There is a brochure published by NHTSA that contains these cues. The title is “The

Visual Detection of DWI Motorists” DOT HS 808 677.

The first category is:

Problems in maintaining proper lane position. [p=.50-.75]

• Weaving.

• Weaving across lane lines.

• Drifting.

• Straddling a lane line.

• Swerving.

• Almost striking object or vehicle.

• Turning with a wide radius.

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 8 of 19

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

• Stopping problems

• Unnecessary acceleration or deceleration

• Varying speed

• 10 mph or more under the speed limit

Speed and Braking Problems

5-11

Speed and braking problems. [p=.45-.70].

• Stopping problems (too far, too short, or too jerky).

• Unnecessary acceleration or deceleration

• Varying speed

• 10 mph or more under the speed limit

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

• Driving without headlights at night

• Failure to signal or signal inconsistent with

action

• Driving in opposing lanes or wrong way on

one way

• Slow response to traffic signals

• Slow or failure to respond to officer’s

signals

• Stopping in lane for no apparent reason

Vigilance Problems

5-12

The third problem is vigilance problems. [P=.55-.65]. This category includes, but is not

limited to:

• Driving without headlights at night

• Failure to signal or signal inconsistent with action

• Driving in opposing lanes or wrong way on one way

• Slow response to traffic signals

• Slow or failure to respond to officer’s signals

• Stopping in lane for no apparent reason

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 9 of 19

DWI Detection and Standardized Field Sobriety Testing

Session 5 – Phase One: Vehicle in Motion

• Following too closely

• Improper or unsafe lane change

• Illegal or improper turn

• Driving on other than designated roadway

• Stopping inappropriately in response to

officer

• Inappropriate or unusual behavior

• Appearing to be impaired

Judgment Problems

5-13

Judgment problems. [P=.35-.90].

• Following too closely (tailgating)

• Improper or unsafe lane change

• Illegal or improper turn

• Driving on other than designated roadway

• Stopping inappropriately in response to officer

• Inappropriate or unusual behavior (throwing objects, arguing, etc.)

• Appearing to be impaired

Notes:_______________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________

HS 178 R5/13 10 of 19Source: DWI Detection and

Standardized Field

Sobriety Testing