Standardized Field Sobriety Tests Drunk driving in the United States

1 standardized field sobriety tests

1.1 horizontal gaze nystagmus test
1.2 walk-and-turn test (wat)

1.2.1 walk , turn test instructions (wat)
1.2.2 walk , turn test evaluation
1.2.3 1 leg stand test (ols)
1.2.4 1 leg stand test evaluation


1.3 field sobriety tests criticisms

1.3.1 walk & turn test criticisms

standardized field sobriety tests

although law enforcement agencies continue use variety of these fsts, use 3-test battery of validated field sobriety tests, referred standardized field sobriety test (sfsts). nhtsa-approved battery of tests consists of horizontal gaze nystagmus test, or hgn test; walk-and-turn test, or wat test, , one-leg-stand test, or ols test.

in states, such ohio, standardized tests admitted evidence, provided administered , objectively scored in substantial compliance nhtsa standards (orc 4511.19(d)(4)(b)).

according nhtsa, these tests not designed measure impairment, rather give probability driver @ or above 0.08% bac. however, studies have shown there reasons doubt tests usefulness in helping officer make such determination. in 1991, dr. spurgeon cole of clemson university conducted study of accuracy of fsts. staff videotaped people performing 6 common field sobriety tests, showed tapes 14 police officers , asked them decide whether suspects had had drink , drive (sic). blood-alcohol concentration of each of 21 dui subjects 0.00, unknown officers. result: officers gave opinion 46% of these innocent people drunk able drive. study showed possible inaccuracy of fsts.

an increasingly used field sobriety test involves having suspect breathe small, handheld breath testing device. these referred pas tests, or preliminary alcohol screening tests , or pbt, preliminary breath test , precede actual arrest , subsequent requirement submit evidentiary chemical test of suspect s breath or blood. these breath testing devices used smaller, inexpensive versions of larger, more sophisticated instruments @ police stations, commonly known evidentiary breath test using ebt device, or evidentiary breath test device. however, increasing number jurisdictions began using portable evidentiary breath test devices, or pebt devices, more sophisticated versions of smaller, inexpensive versions of larger, larger instruments @ police stations. however, larger ebts employ infrared spectroscopy, pebt , pas devices use relatively simple electrochemical (fuel cell) technology. when used purposes of preliminary alcohol screening test, or pas test, purpose, along other fsts, assist officer in determining whether he/she has probable cause arrest.

there 3 tests chosen constitute standardized field sobriety tests , are: (1) horizontal gaze nystagmus test; (2) walk & turn test; , (3) 1 leg stand test.

the horizontal gaze nystagmus test

the horizontal gaze nystagmus test, or hgn test, administered police officer checking test subject s eyes.

horizontal gaze nystagmus instructions (hgn)

horizontal gaze nystagmus evaluation

there 6 cues or clues police officer looking on horizontal gaze nystagmus test, follows:

total cues: 6 cues - decision point: 4/6 cues

while original research indicated 6 out of 6 cues meant person more above 0.08% @ time of test, subsequent research conducted nhtsa has indicated “hit” occurred when number of reported signs given bac fell within range: > 0.06% @ 4–6 cues or clues; .05–.059% @ 2–4 cues or clues; 0.03–0.049% @ 0–4 cues or clues , < 0.03% @ 0–2 cues or clues. robustness of horizontal gaze nystagmus study (september, 2007)

the walk-and-turn test (wat)

the walk-and-turn test composed of 2 phases: instruction phase , walking phase. during test, individual directed take 9 steps along straight line. individual supposed walk heel toe, , while looking down @ real or imaginary line, count steps out loud. test subject s arms must remain @ side. reaching ending point, individual must turn around using series of small steps, , return starting point. proper instruction, according nhtsa guidelines, follows:

walk , turn test instructions (wat)

walk , turn test evaluation

there 8 cues or clues police officer looking on walk & turn test, follows:

total cues: 8 cues – decision point: 2/8 cues

the 1 leg stand test (ols)

the 1 leg stand test composed of 2 stages: instruction phase , balancing phase. proper instruction, according nhtsa guidelines, follows:

one leg stand test evaluation

there 4 cues or clues police officer looking on 1 leg stand test, follows

total cues: 4 cues – decision point: 2/4 cues

field sobriety tests criticisms

critics of standardized field sobriety tests question statistical evidence behind them, , ability of officers administer tests , judge impairments related alcohol. according barone, 1 study involved sober individuals asked perform standardized field sobriety tests, , performances videotaped. after viewing 21 videos of sober individuals taking standardized field tests, police officers believed forty-six percent of individuals had drink . should not out of question standardized field sobriety tests re-examined reliability , validity. standardized test claims have scientific support should able repeated. along that, standardized field sobriety tests not have specific standard grading, , left discretion of officer determine whether he/she see observes cue sufficient count against test subject. err human. nhtsa s 1977 study had error rate of 47 percent, , 1981 study had error rate of 32 percent, considered unusually high scientific study.

one of main criticisms of field sobriety tests judgment left discretion of police officer. officer may have bias towards suspect , judge test more critically necessary. additionally, impossible tell whether or not police officer used proper procedures administering field sobriety test when case brought court. original research conducted nhtsa disputed because of manner in conducted , conclusions reported. 1 author comments reports 3 studies issued nhtsa lacking of material , analysis expected in scientific paper, , none have been published in peer-reviewed journals (rubenzer 2011).

walk & turn test criticisms

one of main problems walk-and-turn test of signs of alcohol impairment may stem other physical problems. along that, there other signs of physical impairment can stem various causes, including fatigue, injury or illness, , nervousness. physically inactive, elderly, or obese may have trouble completing walk-and-turn test without flaw. ntsa used 50 pounds or more overweight may have difficulty performing test, , suspect must walk along real line. later nhtsa manuals removed weight comment, , inserted phrase imaginary line @ instruction phase, though original research used visible line . fact officers no longer required provide line suspect walk along may affect outcome of test, , adds scrutiny received critics.