Effect of γ-hydroxybutyrate (GHB) on driving as measured by a driving simulator.

RATIONALE: Gamma-hydroxybutyrate acid (GHB), a GABAB receptor agonist approved for treatment of narcolepsy, impairs driving ability, but little is known about doses and plasma concentrations associated with impairment and time course of recovery. OBJECTIVE: To assess effects of oral GHB (Xyrem®) upon driving as measured by a driving simulator, and to determine plasma concentrations associated with impairment and the time course of recovery. METHODS: Randomized, double-blind, two-arm crossover study, during which 16 participants received GHB 50 mg/kg orally or placebo. GHB blood samples were collected prior to and at 1, 3, and 6 h post dosing. Driving simulator sessions occurred immediately after blood sampling. RESULTS: Plasma GHB was not detectable at baseline or 6 h post dosing. Median GHB concentrations at 1 and 3 h were 83.1 mg/L (range 54-110) and 24.4 mg/L (range 7.2-49.7), respectively. Compared to placebo, at 1 h post GHB dosing, significant differences were seen for the life-threatening outcome collisions (p < 0.001) and off-road accidents (p = 0.018). Although driving was not faster, there was significantly more weaving and erratic driving with GHB as measured by speed deviation (p = 0.002) and lane position deviation (p = 0.004). No significant impairment regarding driving outcomes was found in the GHB group at 3 and 6 h post dose. CONCLUSION: GHB in doses used to treat narcolepsy resulted in severe driving impairment at 1 h post dosing. After 3 to 6 h, there was full recovery indicating that safe driving is expected the next morning after bedtime therapeutic GHB use in the absence of other substances.

Survey regarding the 0.05 blood alcohol concentration limit for driving in the United States.

BACKGROUND: On May 14, 2013, the National Transportation Safety Board (NTSB) proposed that states lower the blood alcohol concentration (BAC) illegal limit from 0.08 to 0.05 g/dL (also referred to as the 0.08 law and the 0.05 limit, respectively). In March 2017, this recommendation was signed into law in the State of Utah. OBJECTIVE: The objective of this survey is to investigate perceptions regarding enforcement of the 0.05 g/dL BAC limit. METHOD: Opinions of law enforcement officers, prosecutors, and defense attorneys were obtained through a series of questionnaires and focus groups. RESULTS: Survey data were collected from 32 law enforcement officers, 20 prosecutors, and 4 defense attorneys. The participants rated the usefulness of the NHTSA's driving while intoxicated (DWI) driving cues lower for the 0.05 limit than for the 0.08 law. Some of the participants believed that training would be needed in regard to sobriety testing under the 0.05 limit. Participants also stated that adequately preparing for prosecution of drunk drivers would be more difficult under the 0.05 limit. In addition, it was believed that drunk driving cases are more likely to be withdrawn and fewer plea agreements and guilty pleas are likely under the 0.05 limit. Prosecutors were concerned that the 0.05 limit would result in poorly investigated cases and overburden the court system. Defense attorneys were concerned about the social and economic costs of a 0.05 limit. DISCUSSION: Overall, it appears that the 0.05 limit is viewed as enforceable and it will save lives; however, the usefulness of the NHTSA DWI Detection Guide and of the standardized field sobriety tests need to be established for lower BACs, and efforts must be made to educate people regarding the relationship between BAC and impairment and impairment and driving with the risk of injury and death. CONCLUSION: Though the 0.05 limit offers promise in saving lives, the following issues associated with changing the limit to 0.05 need to be resolved prior to implementation: Validating the sobriety tests for the 0.05 limit; if needed, modifying the sobriety tests to make them effective and valid at the 0.05 limit; and training law enforcement personnel and educating the public regarding the 0.05 limit.

The effects of breath alcohol concentration on postural control.

BACKGROUND: Two of the 3 standardized field sobriety tests that U.S. law enforcement uses at roadside checks have a postural equilibrium component to them. Those tests have been validated to detect impairment caused by blood alcohol concentrations (BACs) of 0.08 g/dL or above. Many medical and traffic safety associations support a lower limit, and one state, Utah, has passed a law to lower the limit to 0.05 g/dL. Many studies have examined the effects of alcohol on postural control (of which postural equilibrium is a component), with a consensus emerging that impairment is usually found at BACs greater than 0.06 g/dL. Most of these studies, however, had a relatively small number of subjects, usually between 10 and 30. The current study collected data from a much larger sample. OBJECTIVE: The objective of this study was to provide additional evidence that posture control is negatively affected at BACs greater than 0.06 g/dL or breath alcohol concentrations (BrACs) of 0.06 g/210 L. METHOD: This was a between-subjects study, with BrAC group as the independent variable (5 levels: 0.00, 0.04, 0.06, 0.08, and 0.10 g/210 L); 4 measures of postural control as the dependent variables; and age, height, and weight as the covariates. Posture control was measured with a force-sensing platform connected to a computer. The feet's center of pressure (CoP) on the platform was recorded and the corresponding movement of the body in the anterior-posterior and lateral planes was derived. Participants (N = 96) were randomly assigned to one of the BrAC groups. Positive BrAC groups were compared to the zero BrAC group. Data were examined with hierarchical multiple regression. RESULTS: Adjusted for age, height, and weight, the main effect of lateral CoP with eyes open was not statistically significant. There was a statistically significant main effect of alcohol on anterior-posterior CoP excursion with eyes open and with eyes closed and lateral CoP excursion with eyes closed. For all 3 of those variables, only BrACs of 0.08 and 0.10 g/210 L produced differences against zero BrAC. Although the main effect of alcohol on Lateral CoP Excursion with eyes open was not statistically significant, the contrasts between 0 and 0.08 and 0 and 0.10 g/210L BrAC were in the hypothesized direction. CONCLUSION: The current study did not directly address the issue of whether the sobriety tests are sensitive to BrACs of 0.05 g/210 L or above; rather, it provides additional evidence that postural control, one of the components of those tests, is relatively unaffected by BrACs lower than 0.08 g/210 L. Additional research is needed on the diagnostic characteristics of the sobriety tests at BrACs lower than 0.08 g/210 L.

Effects of alcohol at 0.05% blood alcohol concentration (BAC) on low speed urban driving.

OBJECTIVE: Alcohol-impaired driving presents a continued risk for traffic safety and results in a significant proportion of fatalities on the roadway. We examined how alcohol at a 0.05% blood alcohol concentration (BAC) compares to 0.10% BAC (above the current U.S. legal limit) in terms of impact on driving performance. METHODS: Utilizing a within-subjects design, we recruited 108 healthy experienced drivers who were moderate to heavy drinkers. In a double-blind, placebo-controlled crossover design, we administered placebo and alcohol at the 0.05% and 0.10% BAC levels in a standardized simulated driving protocol. Drives occurred on the descending limb of the blood alcohol curve. This analysis focuses on the urban portion of the drive Results: The study observed clear differences in performance for lateral and longitudinal driving performance and glance behavior. Variability in lane keeping and average speed increased with BAC level, with degraded performance observed at 0.05% BAC. The frequency of lane departures and percentage of time focused on the forward roadway at 0.05% BAC did not differ from placebo but differed from the 0.10% BAC level. CONCLUSIONS: Overall, our results show that there is degraded performance in the urban driving environment and that much of that begins at or below the 0.05% BAC level.

Breath alcohol elimination rate as a function of age, gender, and drinking practice.

The objective of this study was to determine whether breath alcohol elimination rate varies as a function of age, gender, and drinking practice, factorially combined. Eighty-four men and 84 women drank enough alcohol to produce peak BrACs of .110 g/210 L for heavy and moderate drinkers and BrACs of .090 g/210 L for light drinkers. An Intoxilyzer 5000 was used to generate the concentration-time profiles. Mean (M) elimination rates (g/210 L/h) were found to be higher for women (N=84, M=.0182, SD=.0033) than for men (N=84, M=.0149, SD=.0029), F(1, 144)=57.292, p<.001; higher for heavy drinkers (N=56, M=.0176, SD=.0038) than for light and moderate drinkers combined (N=112, M=.0160, SD=.0032), F(1, 144)=12.434, p<.01; and higher for older subjects (51-69 years, N=42, M=.0180, SD=.0038) than younger subjects (19-50 years, N=126, M=.0161, SD=.0033), F(1, 144)=14.324, p<.001. None of the two-way interactions (age × gender, age × drinking practice, gender × drinking practice) or the three-way interaction (age × gender × drinking practice) was statistically significant. Limitations of the current study and suggestions for further research are discussed.

Validation of sobriety tests for the marine environment.

The objective of this project was to develop sobriety tests that can be administered in the seated position to assist water patrol officers in detecting alcohol-related impairment in boaters. Four seated sobriety tests were administered to 330 boaters to determine the tests' usefulness in classifying boaters as having blood alcohol concentrations (BACs) below the illegal limit (BAC<.08%) or above the illegal limit (BAC ≥ .08%). Data were obtained by a team of four marine officers and two civilian observers on Lake of the Ozarks in central Missouri. The overall correct percentages, sensitivity, and specificity of the tests were consistent with what is typically reported in literature on the roadside sobriety tests. The tests' reliability was also consistent with what is typically reported in literature on the roadside sobriety tests. Thus, the four tests may assist marine officers with assessments of alcohol-related impairment in boaters.

Manual versus automatic sampling variations of a preliminary alcohol screening device.

Utilization of a manual sampling function as an alternative to the automatic sampling function in the Alco-Sensor IV Black Dot Model has been recognized by the manufacturer to potentially underestimate an individual's true breath alcohol content (BrAC). A controlled human subject study was conducted to analyze the possible breath-sampling differences between the standard automatic technique and three manual techniques. Subjects were dosed with vodka and orange juice and then tested during the descending limb of their BrAC curve. Differences between the automatic and the manual techniques were found to be statistically significant with the three manual techniques underestimating the BrAC. The average maximum difference between the automatic BrAC level, as compared to the lowest manual level in each data set, was 27.9% (median 27.7%) with underestimations from 20.8% to 40.0%. In no instance did any of the manual techniques produce higher BrACs than the automatic technique.

The Long Beach/Fort Lauderdale relative risk study.

PROBLEM: The role of alcohol as a major factor in traffic crash causation has been firmly established. However, controversy remains as to the precise shape of the relative risk function and the BAC at which crash risk begins to increase. METHODS: This study used a case-control design in two locations: Long Beach, California, and Fort Lauderdale, Florida. Data were collected on 2,871 crashes of all severities and a matched control group of drivers selected from the same time, location, and direction of travel as the crash drivers. Of the 14,985 sample drivers, 81.3% of the crash drivers and 97.9% of the controls provided a valid BAC specimen. RESULTS: When adjusted for covariates and nonparticipation bias, increases in relative risk were observed at BACs of .04-.05, and the elevations in risk became very pronounced when BACs exceeded .10. DISCUSSION: The results provide strong support for .08 per se laws and for state policies that increase sanctions for BACs in excess of .15. IMPACT ON INDUSTRY: This study provides further precision on the deleterious effects of alcohol on driving and, by implication, on other complex tasks.

Cognition, but not sensation, mediates age-related changes in the ability to monitor the environment.

The objective of the study was to determine which age-related changes in sensation and cognition are associated with age-related changes in the ability to monitor the environment. To that end, a proxy measure of the ability to monitor the environment (useful field of view, UFOV) and measures of sensation and cognition were collected from young adult (N = 61) and older adult subjects (N = 79). Although UFOV performance was expected to be mediated primarily by cognition rather than by sensation, it was somewhat unexpected to find no reliable associations between UFOV and sensory functioning beyond those of age and cognition.

Drinking and driving among high-risk young Mexican-American men.

Determinants of driving under the influence of alcohol (DUI) were explored among a sample of relatively young Mexican-American males with limited income and education, high levels of alcohol consumption, and regular vehicle use. Data were collected using questionnaires (N=104) and focus groups (N=27), including a focus group with wives and girlfriends (N=4). Four mechanisms that may contribute to the high rate of DUI behavior in this population were identified: (1) a subculture of permissiveness toward drinking and driving for men, (2) heavy drinking, promoted by machismo and a propensity to measure masculinity with alcohol intake, (3) inadequate knowledge of DUI statutes and inadequate understanding of the relationships between BAC, impairment, and crash risk, and (4) for undocumented drivers, lack of accountability in case of an alcohol-related incident.

Drinking and driving among Mexican American and non-Hispanic white males in Long Beach, California.

Although drinking and driving in the United States has declined substantially during the past two decades, this trend has not been seen among Hispanic drivers. Higher rates of driving while impaired (DWI) arrests and alcohol-related crashes, particularly among Mexican Americans, also have been noted. The extent to which this reflects a lack of understanding of DWI laws rather than a disregard for them is unknown. A survey was conducted among Mexican American and non-Hispanic white male DWI arrestees in Long Beach, California, to ascertain alcohol use, attitudes toward drinking and drinking and driving, and knowledge of DWI laws. The findings were compared with those of Mexican American and non-Hispanic white males recruited from the local community. Mexican American males, both DWIs and those from the community, reported heavier drinking than non-Hispanic white males. All four groups of respondents tended to underestimate the number of drinks needed to achieve the blood alcohol concentration (BAC) threshold at or above which it is illegal to drive under California law. Estimations were around 2-3 drinks rather than a more realistic estimate of 4-5 drinks. However, Mexican American DWIs and their comparison group vastly overestimated the number of drinks to make them unsafe drivers (8- 10 drinks). Furthermore, fewer than half were aware of the BAC threshold in California (0.08%) compared with between 60 and 78% of non-Hispanic whites. This study is limited in scope and needs to be replicated in other communities and with other racial/ethnic groups. However, the clear lack of knowledge of the DWI law in California and a lack of understanding of the relationship between number of drinks and BAC point to the need for culturally sensitive programs that are developed and implemented within the Mexican American community.