1 Joshua Goldberg, Esq. Copyright 2009 How Police Enforce DUI Laws: A Survey of Police DUI Detection and Enforcement Techniques DUI detection is not simply a combination of field sobriety tests and breath or blood tests. DUI detection is a defined term within the police enforcement community. The National Highway Transportation Safety Association (NHTSA) instructs police officers that DUI detection is: The entire process of identifying and gathering evidence to determine whether or not a suspect should be arrested for a DWI violation. National Highway Transportation Safety Association, Student Manual, Feb at IV-1. NHTSA is the preeminent authority on DUI enforcement and it publishes the only nationally recognized Student Manual for police instruction. 1 In order to understand everything about a DUI arrest from A to Z, it is imperative to thoroughly understand the NHTSA manual s instructions for police officers. This paper is a survey of the NHTSA manual, but more importantly, a review of the cornerstone of NHTSA detection: the three phased approach to DUI detection. The phases of DUI detection As pointed out above, the NHTSA student manual instructs officers to collect DUI evidence from the time a vehicle is first spotted until the officer decides whether to arrest the driver. NHTSA breaks this detection process into three easy-to-understand phases: 1) the Vehicle in Motion phase, 2) the Personal Contact phase, and 3) the Prearrest Screening Phase. Id. at IV-3. Officers are instructed to look for specific cues, as well as clues to impairment in each of these phases. Based on the cues and clues detected by the officer, a DUI arrest may be warranted. Phase I: Vehicle In Motion NHTSA draws a distinction between stopping a driver for a motor vehicle violation and stopping a driver based on reasonable suspicion of impairment. Id. at V-1. NHTSA recognizes that officers may initially stop a vehicle solely because of a moving violation. 1 NHTSA is a federal entity which publishes the only nationally recognized manual and testing standards for DUI detection. NHTSA has published these national testing standards for DUI detection and enforcement since The NHTSA manual and its standards were officially adopted by the International Association of Chiefs of Police in 1992.
2 NHTSA instructs officers that, Your first task in Phase One: Vehicle in Motion is to observe the vehicle in operation to note any initial cues of a possible DUI violation. Id. at V-1. NHTSA subdivides Phase 1 cues into: a) visual DWI detection cues, b) stopping sequence cues, and c) post-stop cues. a. Visual DWI Detection Cues NHTSA instructs officers to look for 24 specific Visual DWI Detection Cues. These cues would be exhibited by a vehicle before a traffic stop is initiated. These are: weaving, weaving across lane lines, swerving, turning with wide radius, drifting, almost striking object or vehicle, stopping problems, accelerating or decelerating rapidly, varying speed, slow speed, driving in opposing lanes or wrong way on one-way street, slow response to traffic signals, slow or failure to respond to officer s signal, stopping in lane for no apparent reason, driving without headlights at night, failure to signal or signal inconsistent with action, following too closely, improper or unsafe lane change, illegal or improper turn, driving on other than designated roadway (driving on shoulder, straight in turn only lanes), stopping inappropriately in response to officer, inappropriate or unusual behavior, appearing to be impaired (e.g. eye fixation, tightly gripping the steering wheel, slouching in the seat, gesturing erratically or obscenely, face close to the windshield, and driver s head protruding from vehicle). Id. at V-3-V-7. The 24 Visual Detection Cues are interesting because there is no blanket statement regarding moving violations. Some moving violations (like failure to signal or driving the wrong way on a one-way street) are included in the 24 cues. However, speeding, u-turns, and even equipment violations such as non-functioning headlights, taillights, and brake lights are not included as cues to impairment. Pursuant to the NHTSA manual, the 24 cues were selected over other moving violations because the 24 cues have been found to predict a BAC of.08 or greater. Id. At V-3. b. Stopping Sequence According to NHTSA, cues reinforcing the suspicion of DWI may be found in the stopping sequence. Id. at V-10. NHTSA instructs officers to look for these cues when, the driver responds to your signal to stop. Id. at V-10. Accordingly NHTSA instructs officers to mark whether the following additional cues are evident during the stop of the vehicle: an attempt to flee, no response, slow response, an abrupt swerve, a sudden stop, and striking the curb or another object. Id. at V-10. Conclusion: Phase I As noted above, NHTSA s Phase I of DUI detection encompasses the initial observation of a vehicle and the stop of that vehicle. NHTSA instructs officers to look for very specific cues to impairment: 24 Visual Detection Cues, and another 6 or 7 Stopping Sequence cues. Uneducated officers consistently ignore these cues. A knowledgeable attorney can screen any DUI case to ascertain when an officer has mislabeled detection cues. Phase II: Personal Contact
3 In Phase II, officers are instructed to approach, observe, and interview stopped drivers, and, if warranted, ask the driver to exit the vehicle and observe the manner in which the driver exits and note evidence of impairment. Id. at VI-1. According to NHTSA, Phase II begins as soon as the suspect vehicle and the patrol vehicle have come to complete stops. It continues through your approach to the suspect vehicle and involves all conversations between you and the driver prior to the driver s exit from the vehicle. Id. at VI-1. Phase II culminates in the exit sequence, where the motorist steps and walks from the vehicle. The subcomponents to Phase II are as follows: a. Post Stop Cues Once a stop is made, NHTSA instructs officers to check for the following cues: difficulty with motor vehicle controls, difficulty exiting the vehicle, fumbling with driver s license or registration, repeating questions or comments, swaying, unsteady, or balance problems, leaning on the vehicle or object, slurred speech, slow to respond to officer/ officer must repeat, provides incorrect information/ changes answers, odor of alcoholic beverage from driver. Id. at V-7. b. Driver Interview clues Officers are instructed that face-to-face contact or an interview with a motorist may produce clues or evidence of alcohol influence. Id. at VI-3. These clues are: Bloodshot eyes, soiled clothing, fumbling fingers, alcohol containers, drugs or paraphernalia, bruises/bums/scratches, unusual actions. Slurred speech, admission of drinking, inconsistent responses, abusive language, unusual statements. Smell of alcoholic beverages, smell of marijuana, cover up odors such as breath spray, and unusual odors. Id at VI-3. c. Pre-Exit Interview Techniques. NHTSA recommends that officers detect impairment by a device called divided attention. Three divided attention techniques are recommended to officers. These are: asking for two things simultaneously (e.g. asking the driver to produce both driver s registration and driver s license), asking interrupting or distracting questions (e.g. asking without looking at your watch, what time is it now?), and, asking unusual questions (e.g. what is your middle name?). Id. at VI-4-5. d. Additional techniques. NHTSA neither recommends that officers use the following techniques, nor does it recommend against them. Instead, the NHTSA manual simply identifies these techniques for use
4 during the pre-exit Interview: 1) Alphabet test (NHTSA instructs officers to begin the alphabet at a letter other than A, and end with a letter other than Z. It does not suggest that motorists should say the alphabet backwards!), 2) count down test (e.g. count out loud backwards from the number 68 to 53), 3) finger count (motorist is required to touch the tip of the thumb to the tip of each finger on the same hand while simultaneously counting up one, two, three four; then to reverse direction on the fingers while simultaneously counting down four, three, two, one ). e. The Exit Sequence NHTSA instructs officers, Even though (your suspicion that the driver is impaired) may be very strong, usually the suspect is not yet under arrest when you give the instruction (to exit). Id. at VI-6. How the driver steps and walks from the vehicle and his or her actions or behavior during the exit sequence may provide important evidence of impairment. Be alert to the driver who shows angry or unusual reactions, cannot follow instructions, cannot open the door, leaves the vehicle in gear, climbs out of vehicle, leans against vehicle, keeps hands on vehicle for balance. Id. In conclusion, NHTSA identifies five different parts to Phase II: Personal Contact phase. NHTSA provides officers with many different clues and cues which may be signs of impairment. Officers are expected to memorize these cues and clues, and utilize them in assessing whether a motorist is impaired. Phase III: Pre-Arrest Screening NHTSA instructs officers that, Your first task in Phase III is to administer three scientifically validated psychophysical field sobriety tests. Based on these tests and on all other evidence from Phase One and Two, you must decide whether there is sufficient probable cause to arrest the driver for DWI. Your second task may then be to administer a preliminary breath test (PBT) to confirm the chemical basis of the driver s impairment, if your agency uses PBTs. The entire detection process culminates in the arrest/no arrest decision. Id. at VII-1. NHTSA recognizes only three standardized field sobriety tests: the Horizontal Gaze Nystagmus test, the walk and turn test, and the one legged stand test. NHTSA instructs officers to perform these three tests in conjunction with one another because: beginning in late 1975, extensive scientific research studies were sponsored by NHTSA through a contract with the Southern California Research Institute to determine (which) roadside field sobriety tests were the most accurate... laboratory research indicate that three of these tests, when administered in a standardized manner, were a highly accurate and reliable battery of tests for distinguishing BACs above.10. Id. at VIII-1. In essence, the HGN test, the walk and turn test, and the one legged stand test were selected from many other field sobriety tests as the most accurate combination of tests to enable officers to identify impaired drivers. HGN Test
5 During the HGN test, officers test motorists eyes for involuntary jerking. According to NHTSA, nystagmus, or involuntary jerking of the eyes, is indicative of alcohol intoxication. Specifically, as a motorist s eyes follow a stimulus (such as a pen) the eyes may display a slight jerking. This is especially true if the nystagmus occurs prior to 45%. Officers are trained to look for four of a maximum six clues when performing this test. Walk and Turn Test The walk and turn test consists of having motorists walk a straight line. For the walk and turn test, motorists must take nine heel to toe steps forward on a line, turn while keeping the front foot on the line, and take nine heel to toe steps back on the line. Officers are trained to look for two out of a maximum of eight clues to impairment during the walk and turn test. This means, if the officer detects just two of eight clues, the motorist s BAC is likely to be above.10. The clues are: 1) the motorist cannot keep his or her balance while balancing (at rest) on the line, 2) the motorist begins the test before the officer completes the instructions, 3) the motorist stops while walking, 4) the motorist fails to touch heel to toe while walking on the line (a one half inch space is permissible between the two feet), 5) the motorist steps off the line, 6) the motorist raises his or her arms for balancing (more than 6 inches from the side), 7) the motorist fails to turn with his or her foot on the line on the ninth step, 8) the motorist takes an incorrect number of steps. Id. at VII Again, note that NHTSA does not use the word failure. If an officer observes two or more of the eight clues listed above, the motorist is not said to fail the walk and turn test. Instead, NHTSA states that if an officer detects two or more clues, it is likely that the BAC is above.10. Id. at VII-6. One Legged Stand Test The final field sobriety test in the battery of NHTSA recognized tests is the one legged stand test. For the one legged stand test, motorists must raise one foot six inches off of the ground, keeping his or her foot parallel with the ground, while keeping the planted leg and the lifted leg straight. The motorist must further maintain that position (with his or her arms at the sides) for 30 seconds. Officers are trained to look for two out of a maximum of four clues to impairment. In this test, the clues consist of: Id. at VII-7. 1) the motorist sways while balancing, 2) the motorist raises his or her arms for balancing (more than 6 inches from the side), 3) the motorist hops while performing the test, 4) the motorist puts his or her raised foot down on the ground.
6 Similar to the walk and turn test, NHTSA does not state that a motorist fails the one leg stand test by exhibiting two of the four total clues above. Instead, just as in the walk and turn test, NHTSA states that, The original research shows that, when the suspect produces two or more clues or is unable to complete the test, it is likely that the BAC is above.10. Id. at VII-7. Preliminary Breath Test Results NHTSA recommends the use of hand held breathalyzers, or preliminary breath test (PBTs), but not as a crutch for officers to use when determining whether a motorist is impaired. According to NHTSA, a PBT should only be used by an officer after the field sobriety tests have been performed, and the officer wants to obtain additional confirmation that a motorist s impairment is due to alcohol. According to NHTSA, The PBT result is only one of many factors the officer considers in determining whether the suspect should be arrested for DWI. It should never be the sole basis for a DWI arrest. Id. at VII-7. Further, NHTSA notes, PBT instruments have accuracy limitations. Thus, according to NHTSA, PBTs should be used during Phase III, but the PBT should only be used as a direct indication of alcohol impairment. Id. at VII-7. In sum, the NHTSA Phase III of DWI detection includes the battery of three field sobriety test identified above, as well as a PBT test. Phase III is arguably the most important phase of the DUI arrest because officers must know and understand all 20 potential field sobriety test clues in order to accurately assess whether a motorist is impaired. Attorneys who know and are conversant with all 20 clues to impairment have an edge because officers cannot subjectively suggest that a motorist failed a field sobriety test- because the attorney knows and can impeach the officer on the objective clues to impairment outlined above. Conclusion DUI detection, done the right way, utilizing NHTSA standards, is a complicated process, but it offers the judicial system reliable, objective criteria for DUI enforcement. Having this uniform, objective detection and testing process alleviates a great deal of unfairness and unpredictability in enforcement. While it is true that even the NHTSA standards have their limitations (especially for individuals with leg, knee, back, or weight problems), the standards are far more reliable than tests like the finger to nose test. Because an attorney must be able to impeach officers who fail to obey the NHTSA standards, this paper has outlined the proper NHTSA standards, and surveyed the objective cues and clues to impairment that NHTSA has established. Any officer who does not follow the NHTSA guidelines, and any evidence obtained through a different DUI detection method, should rightly be viewed with skepticism.