10.4  Advanced Roadside Impairment Detection and Enforcement (ARIDE)[1]

ARIDE is “intended to bridge the gap between SFST and DRE courses.”

Note: ARIDE does not include checking for muscle tone, as the Drugs that impair driving course does.


10.4.1 Medical Conditions Which May Mimic Drug Impairment

“There are medical conditions and injuries that may cause a subject to appear to be under the influence of alcohol or other drugs. Some of the more common medical conditions are listed and discussed below:

Head Trauma – A severe blow or bump to the head may injure the brain and create disorientation, confusion, lack of coordination, slowed responses, speech impairment, and other gross indicators similar to those of alcohol and/or drug impairment. Because the injury usually affects one side of the brain more than the other, disparities usually will be evident in the subject's eyes. Sometimes the pupils will be noticeably different in size or one eyelid may droop while the other appears normal. Additionally, the eyes my not be able to track equally while focusing on a stimulus.

Stroke – A stroke will usually produce many of the same effects and indicators associated with head trauma. Stroke victims often will have pupils that are markedly different in size. One pupil may remain fixed and exhibit no visible reaction to light, while the other reacts normally. Paralysis, physical weakness, and other observable signs are often more predominate on one side of the body than the other. Additionally, individuals suffering from a stroke will often have a dazed appearance and be confused and/or scared.

Note: If you suspect a subject is suffering an emerging stroke, call EMS!


Diabetes – A diabetic is most likely to be confused with a person impaired by alcohol or drugs when he or she has taken too much insulin, so that the blood sugar level becomes dangerously low. This condition is sometimes called insulin shock. A diabetic in insulin shock may appear very confused, may be non-responsive, sweat profusely and exhibit elevated pulse rate and blood pressure. If you suspect that you may be dealing with insulin shock, you may be able to give the subject a glass of orange juice, a bite of candy or simply a spoonful of sugar, if they can sit upright and talk normally; that may rapidly produce a noticeable improvement in their condition.

Note: If you suspect a diabetic emergency, call EMS!


Conjunctivitis – This is an inflammation of the mucous membrane that lines the inner surface of the eyelids giving a red, bloodshot appearance of the conjunctiva of the eyes. At first glance, this may appear similar to the bloodshot conditions associated with impairment by alcohol or cannabis. This condition may occur in one or both eye and is often referred to as ‘pink eye’.


Shock – Shock is a life-threatening condition that occurs when the body is not gettingenough blood flow. This can damage multiple organs and lead to death. Subjects who are in shock often will appear dazed, uncoordinated and non-responsive.

Note: Shock requires IMMEDIATE medical treatment and can get worse very rapidly.


Multiple Sclerosis – Victims of Multiple Sclerosis (MS) and other degenerative muscular disorders may lack coordination or exhibit gait ataxia, tremors, slurred or garbled speech, and many of the other gross motor indicators of intoxication. Unlike many under the influence of alcohol and/or drugs, MS sufferers usually appear alert.


Other Medical Conditions – Some other medical conditions that may cause signs and symptoms similar to drug impairment include: carbon monoxide poisoning, seizures, endocrine disorders, neurological conditions, psychiatric conditions, and infections.


Behavioral Conditions – There are some behavioral conditions that may affect demeanor, general appearance, and vital signs. Some examples would include exercise, excitement, fear, anxiety, and depression.


10.4.2 Drug Classifications Central Nervous System Depressants

“In order for a drug to be classified as a depressant according to the DEC program, it must depress the activity of an individual’s brain and the Central Nervous System. The CNS Depressant category initially affects functions such as speech, coordination, and mobility.

As the dosage increases (amounts usually greater than therapeutic doses), impairment of  the body’s autonomic nervous system, such as heartbeat, body temperature, and breathing may be observed. In addition to alcohol, the depressant category also includes anti-anxiety tranquilizers, anti-psychotic tranquilizers, antidepressants, barbiturates, non-barbiturates, or combination drugs.

People under the influence of CNS Depressants may look and act very much like people under the influence of alcohol. You may encounter an individual that appears to be “drunk,” but lacks any breath odor of an intoxicating beverage[2].”

“General Indicators:

Wide variety of emotional effects (euphoria, depression, and laughing or crying for no apparent reason)  • Reduced ability to divide attention  • Disoriented  • Sluggish  • Thick, slurred speech  • Drunk-like behavior  • Droopy eyes • Fumbling • Relaxed inhibitions • Slowed reflexes • Uncoordinated • Drowsiness • Gait ataxia (rubber legged)[3].”

“Conditions That May Mimic Drug Impairment

There are several conditions that may mimic impairment by a CNS depressant.

These may be, but are not limited to:

Extreme fatigue • Very recent head injuries • Diabetic reactions • Hypotension (low blood pressure) • Inner ear disorders • Severe depression”[4]


“Eye Indicators: HGN – Present. VGN – May be present, especially in high doses. Pupil Size – Normal (Exception Soma/Quaaludes which cause dilation). LOC – Present[5].” Central Nervous System Stimulants

CNS Stimulants influence the human body by speeding up, or over stimulating the brain. Cocaine, amphetamines, methamphetamine, and Ritalin are examples of CNS Stimulants.

“CNS Stimulants relieve fatigue, aid in weight reduction, reduce the need for sleep, and increase energy and confidence levels. In general, it brings about both a psychological and physical exhilaration. CNS Stimulants are commonly known as “uppers” and their effects are similar to the body’s flight or fight responses. As stimulants “wear off”, the subject can exhibit signs and symptoms similar to those associated with depressants since some of the body’s systems may experience a “crash.”[6].”


“Effects of CNS Stimulants

The main effect of most CNS Stimulants is euphoria – an extremely pleasurable sensation. This is only true while the high is felt. You may find an opposite effect as the drug wears off. While the drug is psychoactive, the subject may seem as their system is sped up or in fast forward, but as the drug leaves the system (crashing), this person may appear as though they are under the influence of a CNS depressant.

General Indicators:

Restlessness,Body tremors, Excited, Euphoric, Talkative, Exaggerated reflexes, Anxiety, Grinding teeth (bruxism), Redness to nasal area, Runny nose, Loss of appetite, Increased alertness, Dry mouth, Irritability[7]

“Conditions That May Mimic Drug Impairment

There are several conditions that may mimic impairment by a CNS stimulant.

These may be, but are not limited to:

• Hyperactivity• Nervousness • Stress • Fear • Hypertension (high blood pressure)[8].”

Eye Indicators: HGN – None. VGN – None. Pupil Size – Dilated. LOC – None.[9] Hallucinogens

“Hallucinogens are drugs, which affect a subject’s perceptions, sensations, thinking, self- awareness and emotional state. The category is classified in this manner because one of the significant effects of these drugs is hallucinations. A hallucination is a sensory experience of something that does not exist outside the mind. An example would be seeing something that does not exist or hearing a color.[10]

“Effects of Hallucinogens

The user can feel a wide variety of effects when using hallucinogens. The effects depend on the personality and expectations of the subject, as well as the surroundings in which the drug is taken. The drug generally intensifies the mood of the user at the time of ingestion. If the user is depressed, you could observe a deeper depression, and if the user is feeling pleasant, you could see a heightened pleasure. However, hallucinogens can uncover emotional or psychological issues in the user. Therefore, the user may expect a pleasurable “trip”, but end up instead with a bad “trip.”[11].”


“General Indicators

• Hallucinations • Paranoia • Nausea • Perspiring • Dazed appearance • Flashbacks • Body tremors • Uncoordinated • Disoriented • Memory Loss • Synesthesia (mixing of the senses) • Difficulty in speech.[12]

“Conditions That May Mimic Drug Impairment

There are two conditions that may mimic impairment by a hallucinogen. These may be,

but are not limited to:

• High fever • Mental illnesses.[13]


“Eye Indicators: HGN – None.VGN – None. Pupil Size – Dilated. LOC – None.[14] Dissociative Anesthetic (DA)

“The DA category includes Phenyl CyclohexylPiperidine (PCP) along with its analogs, as well as dextromethorphan (DXM). An analog of a drug is one with a similar chemical composition. Analogs have slightly different chemical structures but produce the same effects.

A DA is often hard to recognize as its own category because the effects or symptoms displayed are sometimes similar to those found in individuals under the influence of hallucinogens, stimulants and depressants. If a thorough assessment is not performed, the officer may jump to an incorrect conclusion.[15]

“General Indicators:

Perspiring, Blank stare, Cyclic behavior, Chemical odor, Increased pain threshold , Incomplete verbal responses, Warm to the touch, Repetitive speech, Hallucinations, Confused, Possibly violent and combative, “Moon walking.”[16]

“Conditions That May Mimic Drug Impairment

Mental illnesses may mimic impairment by Dissociative Anesthetics.[17]


“Eye Indicators: HGN – Present. VGN –Present. Pupil Size – Normal. LOC – Present.[18] Narcotic Analgesics

“Drugs in the Narcotic Analgesics category relieve pain. They induce euphoria, alter moods, and produce sedation. Narcotic Analgesics are also included in the opiate family and are both legal prescription medications as well as illegal drugs. This category is known for its physically addicting properties and severe withdrawal symptoms.[19]

“General Indicators:

• Droopy eyelids • “On the nod” • Drowsiness • Depressed reflexes • Dry mouth • Low, raspy, slow speech • Euphoria • Fresh puncture marks • Itching • Nausea • Track marks.”[20].”

“Conditions That May Mimic Drug Impairment

There are several conditions that may mimic impairment by a narcotic analgesic.

These may be, but are not limited to:

• Fatigue • Very recent head injuries • Diabetic reactions • Hypotension (low blood pressure) • Severe depression.[21]

“Eye Indicators: HGN – None.VGN – None. Pupil Size – Constricted. LOC – None.[22] Inhalants

“Inhalants vary widely in terms of the chemicals involved and the specific effects they produce. Inhalants are one of the most accessible and inexpensive substances of abuse due to their legitimate applications. They are relatively inexpensive as well as readily available in the home, school, or work environment.[23]

“Effects of Inhalants

The effects of inhalants will vary widely depending on the substance inhaled. Typically the inhalant abuser will generally appear similar to someone who is impaired by alcohol. Inhalant abusers can be detected and distinguished from other drug abusers because they will usually carry the chemical odor of the inhaled substance about their breath and person.[24]

“General Indicators:

• Confusion • Flushed face • Intense headaches • Bloodshot, watery eyes • Lack of muscle control • Odor of substance • Non-communicative • Disorientation • Slurred speech • Possible nausea • Residue of substance around mouth and nose.”[25]


“Conditions That May Mimic Drug Impairment

There are two conditions that may mimic impairment by an Inhalant. These may be, but are not limited to:

• Severe head injuries • Inner ear disorders.[26]


“Eye Indicators: HGN – Present. VGN – Present (In high dose for particular individuals). Pupil Size – Normal (May be dilated). LOC – Present.[27] Cannabis

“Cannabis is a category of drugs derived primarily from various species of plants, such as the Cannabis Sativa and Cannabis Indicia. The drugs in this category are the most widely abused illicit drugs. They can be extremely impairing even though they are often believed to be fairly benign.

The primary psychoactive ingredient in Cannabis is Delta-9 Tetrahydrocannabinol (THC)[28].

THC is found primarily in the leaves and flower of the marijuana plant. Different varieties of Cannabis contain various concentrations of THC. Marijuana is usually found as greenish, brown plant material. It is typically packaged in plastic baggies or other small devices.[29]

“General Indicators:

• Marked reddening of the conjunctiva • Odor of marijuana • Marijuana debris in the mouth • Body tremors • Increased appetite • Relaxed inhibitions • Disoriented • Possible paranoia • Impaired perception of time and distance • Eyelid tremors.[30]

“Eye Indicators: HGN – None.VGN – None. Pupil Size – Dilated. LOC – Present.[31]


“Conditions That May Mimic Drug Impairment

Generally speaking, cannabis impairment will not be confused with any other medicalcondition as noted in the other drug categories. However, a subject who has been diagnosed with an attention deficit disorder may mimic a cannabis user’s inability or unwillingness to pay attention[32].”


10.4.3 Polydrug Use

“Effects of Drug Combinations

For the purpose of this course, polydrug use occurs when a person ingests drugs from two or more different drug categories into their body. Each drug may work independently, but what the body will exhibit, however, is a combination of the effects of each drug. Polydrug use is very common, therefore it is important for law enforcement and other criminal justice professionals to have a basic understanding of how ingesting more than one drug category might affect the behaviors commonly associated with an impaired driver.[33] Null Effect

“The simplest way to explain the null effect is using the phrase - "zero plus zero equals zero." Another way of describing this is a case: “Nothing plus nothing equals nothing”


0+0=0.[34] Overlapping Effect

"Something plus nothing equals something.”

Or 1+0=1

The overlapping effect comes into play when one drug does affect an indicator of impairment and the other drug has no affect on that indicator.[35]

“Action plus no action equals action.[36] Effect

“The additive effect occurs when two drug categories affect the same indicator in the same way. In other words, the effects ‘add together’ or reinforce each other to produce a greater effect than one of the drugs could produce individually[37].”

“Action plus action equals a greater action”[38]. Effect

“An antagonistic effect occurs when two drug categories affect some indicator in exactly the opposite ways. This is explained with the phrase one plus a negative one equals anything. Another way of describing this is: Action plus an opposite action may be unpredictable. [39]


10.4.4 Lack of Convergence Test

Besides the typical eye exams (checking pupil size, HGN, and VGN), ARIDE informs the officer on how to check for Lack of Convergence.

“Administration of the LOC Test

The procedures for administrating this test are listed below. The procedures are divided into two stages: instruction and testing.

Instruction Stage: Initial Positioning and Verbal Instructions

1. Position the stimulus approximately 12-15 inches in front of the suspect’s nose in the same position as used in the HGN test.

2. Inform the suspect that you will be moving the stimulus around in a circle, and will be moving it toward the bridge of their nose. In addition, inform the suspect that you will not actually touch the nose with the stimulus. This notice is important so the individual will not move their head away.

3. Instruct the suspect to keep their head steady and to follow the stimulus with their eyes only.

Testing Stage:

1. Start moving the stimulus and make two circles in front of the suspect’s face, either in a clockwise or counterclockwise motion. Observe the eyes to verify the suspect are tracking the stimulus.

2. Slowly move the stimulus in toward the bridge of the suspect’s nose stopping at approximately 2” from the bridge of the nose. Do not touch the bridge of the nose with the stimulus.

3. Hold the stimulus 2” from the bridge of the suspect’s nose for approximately one (1) second and then remove it, while continuing to observe the suspect’s eyes”[40].





Lack of Convergence


“Test Interpretation

The suspect’s eyes should come together and cross (converge) as they track and remain aligned with the stimulus. If the eyes are able to cross (converge), i.e., if they both come together when the stimulus is stopped approximately 2” from the bridge of the suspect’s nose, lack of convergence is “not present.” But, if one eye drifts away or outward toward the side instead of converging toward the bridge of the nose, lack of convergence is “present.”[41].”

“There are no clues associated with the LOC test. The law enforcement officer should note whether or not convergence is present and document their observations as to the movement of the eyes during this test[42].”


10.4.5. Modified Romberg Test

This test is basically the same version as given in the other training courses. However, because the language is not identical, I am providing the full test instructions.

“The Romberg Balance Test, which is used as part of the Drug Evaluation and Classification Program as well as this course, is adopted from its original use as a neurological assessment tool in order to check a suspect’s internal clock, balance and presence of tremors (eyelid and body). . Since part of the Romberg Balance Test checks for balance, care should be taken to ensure the test is conducted on a level surface and in an environment which is appropriate for this type of test when conducted at roadside[43].”

“Administrative Procedures:

Instruction Stage: Initial Positioning and Verbal Instructions

1. Instruct the suspect to stand straight with their feet together and the arms down at their sides.

2. Tell the suspect to remain that position while you have finished giving the instructions. Emphasize that he or she must not start the test until you say "begin.”

3. Ask the suspect if he or she understands the instructions so far.

4. Tell the suspect that, when you tell them to, they must tilt their head back and close their eyes. DEMONSTRATE how the head should be tilted, but DO NOT CLOSE YOUR EYES while demonstrating.

5. Tell the suspect that when you say "Begin," they must estimate to themselves the passage of 30 seconds.

Note: DO NOT tell the suspect to "count to thirty seconds" or to use any other specific procedure to keep track of time."

6. Tell the suspect that, when they think the 30 seconds have gone by, they must bring their head forward, open their eyes, and say "Stop."

7. Ask the suspect if they understand.

Balancing Stage:

1. Instruct the suspect to tilt their head back and close their eyes.

2. Look at your watch and pick a convenient time to start the test.

3. Tell the suspect to begin.

4. Keep track of time while the suspect performs the test.

5. Check suspect for presence of tremors (eyelid and/or body) and sway.

6. When the suspect opens the eyes, ask them "how much time was that?"

Note: If 90 seconds elapse before the suspect opens their eyes, stop the test.[44]

“Test Interpretation

There are no pass/fail criteria or clues associated with the modified Romberg Balance Test. Document the actual number of the seconds which passed during the test. If the suspect’s estimation of time is between 25-35 seconds, then their internal clock is considered acceptable. The presence of any tremors, as well as the occurrence, degree, and direction of any sway should be documented. Other observations can be conducted during this test including, looking into the nasal cavity for signs of ingestion, muscle rigidity, skin color, etc. Any additional observations should also be documented.[45]

[1]Advanced Roadside Impaired Driving Enforcement,  NHTSA 11/07

[2]Id. at VI-3

[3]Id at VI-4

[4]Id. at VI-5

[5]Id. at VI-4

[6]Id. at VI-7

[7]Id. at  VI-8

[8]Id. at VI -8

[9]Id. at VI -9

[10]Id at VI-10


[12]Id. at VI-11

[13]Id. at VI -12

[14]Id. at VI-11

[15]Id. at VI-12

[16]Id. at VI-14

[17]Id. at VI-15

[18]Id. at VI-14

[19]Id. at VI-15

[20]Id. at VI-16

[21]Id. at VI-17

[22]Id. at VI-16

[23]Id. at VI-18


[25]Id at VI-19

[26]Id at VI-20

[27]Id at VI-19

[28]Practice Note: – The Carboxy metabolite of THC in not psychoactive

[29]Id. at VI-20

[30]Id. at VI-21

[31]Id. at VI-22

[32]Id. at VI-22

[33]Id. at VII-3

[34]Id. at VII-4

[35]Id. at VII-5

[36]Id at VII-5

[37]Id at VII-5

[38]Id at VII-6

[39]Id at VII-6

[40]Id at V-5


[42]Id at V-6

[43]Id at V-7

[44]Id. at 7-8

[45]Id at 9