Alcohol driving tests

Several studies have found that cannabis and alcohol produce additive detrimental effects on driving performance, but other studies have failed to show any potentiation. This is probably due to the variety of simulated driving tests used and possibly the time lag between the administration of alcohol and cannabis behavioural impairment after cannabis has been reported to peak within 30 minutes of smoking. Nevertheless, both drugs have been shown to affect some aspects of driving performance and increase the risk of fatal car accidents. Concurrent use of cannabis and alcohol before driving should therefore be avoided. 

A double-blind, crossover study in 20 healthy subjects given various combinations of alcohol and either doxepin or a placebo found that with blood-alcohol levels of 40 to 50 mg% their choice reaction test times were prolonged and the number of mistakes increased. Coordination was obviously impaired after 7 days of treatment with doxepin, but not after 14 days. In an earlier study doxepin appeared to cancel out the deleterious eftects of alcohol on the performance of a simulated driving test. It appears that doxepin may be more toxic when given with alcohol and it has been suggested that a less dangerous alternative could be chosen when indications of alcohol abuse or suicide risk are present. ... 

Alcohol. The number of driving under the influence of alcohol (DUl) cases reflects the enormity of the dmnken driving problem in the United States (9). Tests to measure blood alcohol concentration are conducted on blood, urine, or breath (10). In the case of urine and breath, the alcohol concentration measured is reported in terms of the equivalent blood alcohol concentration. Most states in the United States presume that a person is under the influence of alcohol with respect to driving a motor vehicle at a blood alcohol concentration of 0.10%, ie, an ethanol concentration >10 g/100 mL of blood. Some states maintain a lower necessary concentration of 0.08%. In some European countries levels are as low as 0.05%. A blood alcohol concentration of 0.10% in a 68-kg (150-lb) person is the equivalent of about four drinks of 80 proof alcohoHc beverage or four 340-g (12-oz) beers in the body at the time of the test (see Beer Beverage spirits, distilled Wine). Ethanol is metabolized at the equivalent rate of about one drink per hour. 

Other Substances. Driving under the influence of alcohol cases are compHcated because people sometimes consume alcohol with other substances (11—13). The most common iUicit substances taken with alcohol are marijuana and cocaine (see Table 1) (14). In combination with alcohol, some dmgs have an additive effect. When a blood or urine alcohol sample is tested for alcohol and the result is well below the legal concentration threshold yet the test results are not consistent with the arresting officers observation that the subject was stuporous, further toxicological tests for the possible presence of dmgs are indicated. 

The police may pull over a driver weaving erratically on the highway on suspicion of drunk driving. A police officer must confirm this suspicion by assessing whether the driver has a blood alcohol concentration over the "legal limit." The "Breathalyzer" test checks a person s breath using a redox reaction to determine blood alcohol concentration. This test was invented in 1953 by Robert Borkenstein, a former member of the Indiana State Police, and a professor of forensic studies. 

Some crystal substances, such as copper sulfate, have water locked into them. This is known as "water of crystallization, and may affect their color. If blue copper sulfate is heated to drive the water away, a whitish powder is formed - "anhydrous (waterless) copper sulfate. This can be used to test for water. When a liquid such as( pure alcohol is poured onto the powder, there is no color change. But if any water has been added to the alcohol, the copper sulfate powder will turn blue again. This is because it has taken some water from the alcohol-water mixture tp re-form the blue crystals. 

A unique and considerably more elaborate multiaxial test employs a thick-walled hollow sphere test specimen which may be pressurized internally or externally with a nearly incompressible liquid. Figure 20 illustrates the essential features of the test device as described by Bennet and Anderson (5). The specimen is prepared by casting propellant in a mold fitted with a sand-poly (vinyl alcohol) mandrel inside the sphere which may be removed easily after curing. A constant displacement rate instrument drives the piston to pressurize the chamber and apply large deformations. The piston s total displacement volume is transferred to... 

Over 90% of alcohol consumed is oxidized in the liver much of the remainder is excreted through the lungs and in the urine. The excretion of a small but consistent proportion of alcohol by the lungs can be quantified with breath alcohol tests that serve as a basis for a legal definition of "driving under the influence" in many countries. At levels of ethanol usually achieved in blood, the rate of oxidation follows zero-order kinetics that is, it is independent of time and concentration of the drug. The typical adult can metabolize 7-10 g (150-220 mmol) of alcohol per hour, the equivalent of approximately one "drink" [10 oz (300 mL) beer, 3.5 oz (105 mL) wine, or 1 oz (30 mL) distilled 80-proof spirits]. 

Fig. 7. Diagrams of the schemes for modifying levels of A, alcohol dehydrogenase and B, pyruvate decarboxylase activity and testing for survival of anoxia. In A, constructs contain the 35S promoter of the cauliflower mosaic virus (35S) driving expression of the cotton Adh cDNA in either the sense (Adh) or antisense (hdA) orientation, linked to the 3 termination signal of the nopaline synthase gene (Nos). Alternatively, the expression of cotton Adh cDNA is under control of the pea Adh promoter sequence (pea Adh). In B, either the 35S promoter or the pea Adh promoter is used to drive expression of the maize pyruvate decarboxylase cDNA (Pdc), linked to a Nos 3 termination sequence. Constructs are introduced into cotton via Agrobacterium tumefaciens-mediated infection of cotton. Transformed cotton callus is then assayed for its ability to survive anoxia.

Alcohol and Car Driving The effects of alcohol and driving are a subject of great importance, as many countries have made laws designed to prevent car accidents. Accidents involving alcohol number as many as 50% of total accidents (Fig. 14-1). Hence, it is necessary to perform breath or blood tests to determine a driver s alcohol content. In the United Kingdom, a blood-alcohol level exceeding 80 mg/100 mL is an offense other countries such as the United States and Australia have lower limits. 

---