How Do Police Officers Measure DUI Impairment from Drugs

By San Diego Attorney on November 5, 2022

Aside from DUI checkpoints, police in California need reasonable suspicion to pull you over – facts that would lead a reasonable person to believe that a crime has taken place or will take place, and that further investigation is warranted. If you were weaving excessively, driving erratically, ran a stop sign, or had a brake light out or a cracked windshield, you may be subjected to a traffic stop. Once they pull you over, officers will be looking for signs of driving under the influence of alcohol or drugs.

What Signs of Alcohol or Drug Impairment Do Police Officers Look For?

In a traffic stop or DUI checkpoint, police look for physical and behavioral signs of alcohol consumption, such as:

• Flushed face
• Bloodshot or watery eyes
• Odor of alcohol
• Slurred speech
• Slow response
• Nonsensical speech

When police suspect drug impairment, they may call in a drug recognition expert (DRE). Physical signs of drug use police look for include:

• Sweating
• Dilated pupils
• Coated tongue
• Drug remnants on skin or nostrils

Are Field Sobriety Tests Different for Drugs Than for Alcohol?

If they believe it is warranted, police officers may administer field sobriety tests on the side of the road after a traffic stop. Although there are different types of field sobriety tests, the three standardized tests used by California police to detect both marijuana and alcohol impairment are:

• Horizontal Gaze Nystagmus Test: The officer moves an object or a finger from side to side in front of the suspect’s face to detect involuntary jerking of the eye associated with intoxication.
• Walk and Turn Test: The officer instructs the suspect to walk and turn in a particular manner, and watches to detect loss of balance, inability to walk a straight line, failure to follow instructions, etc.
• One Leg Stand Test: The suspect is instructed to lift one foot off the ground, remain still, count, and look down. Police watch for swaying, hopping, or putting the foot down.

Incorrect administration of field sobriety tests is not uncommon. Police officers may give incorrect instructions for the Walk and Turn Test or the One Leg Stand. While administering the Horizontal Gaze Nystagmus Test, officers may not perform the test properly or they may not account for natural nystagmus (rapid, involuntary eye movement) that occurs in people who are not impaired.

What Charges Could You Face for Driving Under the Influence of Drugs?

Driving under the influence of drugs (DUID) is usually charged as a misdemeanor in California. Penalties may include possible jail time, DUI probation for three to five years, a fine of approximately $1,800, and DUI School. For a fourth or subsequent DUI offense, if it caused injury to a third party, or if the defendant has a prior felony DUI conviction, DUID is charged as a felony. In this case, it carries stiffer penalties, including up to three years in jail, or up to four years if a third party was injured.

How Can a San Diego Defense Lawyer Help?

If you have been charged with DUID, you need a San Diego DUI of drugs defense attorney to protect your rights and freedom. Your lawyer can raise legal defenses against the charges, depending on the circumstances of your case. For example, marijuana stays in the system long after its intoxicating effects are gone, and the prosecution may have no clear evidence that you were impaired at the time of driving. Field sobriety tests and even chemical testing can be inaccurate.

Contact jD Law Criminal Defense Attorneys at (760) 630-2000. Founding attorney James N. Dicks is a former LAPD investigator and a drug recognition expert who keeps current with the latest developments in the field.