I wonder how police officers work in Los Angeles, California in finding out those who are driving under the influence. How do police officers detect drunk drivers on the road?

Liz

Los Angeles, CA

Building upon a previous research of the National Highway Traffic Safety Administration (NHTSA), researchers did some interview with officers from across the country and developed a list of more than 100 driving cues that have been found to predict blood alcohol concentration (BAC) of 0.08% or higher. The list was later on reduced to 24 driving cues during three field studies involving hundreds of officers and more than 12,000 enforcement stops. The driving behaviors identified by the police officers are divided into four categories: problems in maintaining proper lane position, speed and braking problems, vigilance problems, and judgment problems.

The cues that are presented in the four categories predict that a driver is under the influence at least 35% of the time. For example, if a driver is weaving or weaving across lane lines, the probability of DUI is more than 50%. But if you observe any of the weaving cues and any other cue, the probability of DUI jumps to at least 65%. This is how police officers in Los, Angeles, California observe motorists to find out those who are driving under the influence.

I heard from my mom that field sobriety tests are used to be called something else back then. How were these tests develop and could you cite some common tests that police usually conduct here in Los Angeles, California?

Amos
Los Angeles, CA

In mid 1970’s, with the assistance and cooperation of the law enforcement community, the National Highway Traffic Safety Administration (NHTSA) has conducted research that resulted in the development of a battery of three standardized field sobriety tests (FST’s). These are the Horizontal Gaze Nystagmus, Walk and Turn and the One Leg Stand which are commonly used by police officers in Los Angeles, California and are designed to assist them in detecting drivers who are under the influence. FST’s are formerly referred to as Improved Sobriety Tests but they are now the Standard that the Federal Government wants to be utilized.

The FST program was validated in field studies and laboratory conducted by the Southern California Research Institute. The FST’s were initially developed by the Los Angeles Police Department Training in how to conduct the tests and it is included in the NHTSA course “DWI Detection and Standardized Field Sobriety Testing.”