How Oklahoma Police Officers Detect and Detain Suspected Drunk Drivers: Part One

When it comes to making DUI stops, it is well-established in Oklahoma and other states that police officers cannot arbitrarily stop vehicles and then “work backwards” to try to find something illegal. The stop itself must have some basis in reasonable suspicion that the driver is driving while under the influence. But how do police make such a determination? Is there any uniform standard that they adhere to, and if so what is that standard?

 

Police in many jurisdictions do in fact have guidelines to help them decide whether to pull over a vehicle the driver of which they suspect is intoxicated. One such set of guidelines is issued by the US Department of Transportation’s National Highway Traffic Safety Administration (NHTSA), and is entitled “DWI Detection and Standardized Field Sobriety Testing.”  It is important to realize that this manual is more than just how to perform the roadside field sobriety tests but also trains an officer when he should stop a vehicle suspected of DUI or DWI. 

The NHTSA standards visualize a police DUI stop as a three-phase process that begins with observing the vehicle in motion, then progresses through making personal contact with the driver and finally to pre-arrest screening. This post will address the first of these three phases, “vehicle in motion.” 

This first phase is intended to answer the question, “Should I stop the vehicle?” Depending on the circumstances, the officer will answer the question in one of three ways:

●       Stop the vehicle right away

●       Wait and look for additional evidence

●       Do not stop the vehicle

Driving a car involves a process known as “divided attention.” A sober driver must be able to handle multiple tasks simultaneously, or near-simultaneously, such as steering, signaling, controlling the accelerator and brakes, and observing other cars and traffic signals. 

Impaired drivers have trouble dividing their attention; they tend to concentrate on only a few critical tasks at any given time, letting the other tasks slip. These drivers frequently demonstrate symptoms that police are trained to look for, such as slowed reactions, poor coordination, impaired vision or impaired judgment.  

There are, in fact, more than 100 driving cues that may indicate DUI behaviors, which fall into broader categories:

●       Problems maintaining proper lane position

●       Speed and braking problems

●       Vigilance problems

●       Judgment problems 

Thus, police officers in phase one will be observing the vehicle to see if the driver exhibits behaviors like committing a moving traffic violation, swerving or weaving in a lane or across lanes, turning with an unusually wide radius, or driving at an unusually slow speed or with varying speeds.  

The NHTSA standards even suggest the possible level of alcohol intoxication that these behaviors may indicate:

●       Slowed reactions: blood alcohol concentration (BAC) of 0.03

●       Impaired judgment: BAC of 0.05

●       Impaired vision: BAC of 0.08

●       Poor coordination: BAC of 0.10

Other things that police will look for include expired registration tags or movement in the car indicating that the driver is drinking something or otherwise taking drugs. 

The officer’s decision whether to move to the second phase -- stopping the vehicle and interacting with the driver -- can depend on the severity of the impairment symptoms that he or she sees. Dangerous behaviors, such as nearly striking other vehicles or objects or driving with one’s headlights off at night will likely result in an immediate stop; less severe behaviors, like driving slowly or drifting within a lane may lead the officer to wait and see if the driver displays other symptoms. 

In a following post, we will consider phase two of the three-phase process: the vehicle stop and the officer’s communication with the driver. 

Every one of our Oklahoma DUI Lawyers as well as most of our support staff at the Hunsucker Legal Group are trained and certified in NHTSA DWI Detection and Field Sobriety Testing.  It is our goal that we will be better trained and have more knowledge that the prosecutor and the police officer when we step into a courtroom to protect our clients.  For a frre consultation, please call 405-231-5600.