Some Observations on 'the Effects of the Consumption of Alcohol and its Relation to

Road Traffic

EDGAR RENTOUL

Lecturer

HAMILTON SMITH

Research Fellow

RICHARD BEAVERS

Senior Technical Assistant

Department of Forensic Medicine

T h e University of Glasgow, Scotland

A detailed examination was made of the effect o f ten ounces of whisky on twenty subjects. I t was found that the variations i n the effects from one individual to another were very much greater than had been expected. Consideration was also given to the effectiveness of the Standard Tests in deciding jitness to drive a car. These were found to be unsatisfaclory. A series of urine alcohol estimations has been made and the quantity of alcohol present has inzlariably been very much less than would have been exbected from theoretical calculations.

Reaction times were taken of individuals at various levels of intoxication and it was found that deterioration in visual reaction time was #resent at all levels.

A simple visual reaction timer i s described and some suggestions are made for dealing with the Alcohol Road Traffic Problem.

The effects of alcohol have for long been a source of delight and trouble for the human race. In recent years the scientific investigation of the effects of alcohol has become important because of the increasing density and speed of our road traffic.

I t has always been generally recognised that a man does not drive a motor car well when he is drunk. The question of the effect of quantities of alcohol less than that required to produce obvious drunkenness has, however, always been a somewhat controversial one. We all know of people who in their own opinion, and even in that of some of their friends, drive better after two large whiskies. Most workers who have made a study of the subject, including the present writers, have dismissed this as one of the many myths which have grown up around the process of drinking. I t was, therefore, somewhat alarming to find the highest scientific confirmation of this. The M.R.C. Memorandum No. 38, which dealt with the " Effect of Small Doses of Alcohol on a Skill Resembling Driving," reported that of the forty people tested, varying numbers of individuals improved at different aspects of driving, but the really surprising finding was that five of the forty showed an improvement in all aspects of driving, in that they drove more slowly, more consistently and made less error.

As a result of these findings, the differing opinions on the effects of alcohol scattered throughout the literature, and personal experience of the different standards employed by medical examiners when examining drunken drivers, an attempt was made to find some basic alteration in performance which is common to all individuals who have taken alcohol. A further part of the investigation was directed to relating the variations in performance to the urine

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alcohol level of the individuals, and in connection with this we were specially interested to discover whether by retaining the urine from the time of the initial intake of alcohol there could be a period when one might get a urine alcohol figure which could not be related to the blood alcohol level in the usually accepted figure of one point three to one. We were concerned about this because the point has been frequently raised by Defence Counsel when we have been giving evidence on urine alcohol levels in Road Traffic Act cases. We have also been concerned about this because when making post-mortem dissections we have occasionally found a relatively high urine alcohol in comparison wit11 the blood alcohol figure.

In the main part of this investigation we have given each individual ten ounces of seventy degrees proof whisky (this is the strength of whisky usually drunk in this country). They were permitted to take the whisky either neat or with water, and they were asked to drink it as quickly as possible. The drinking period varied from five to fifteen minutes. There are two points of interest in connection with this. Whisky was given because i t is a common alcoholic drink and we felt that some of the work which has been done was not completely reliable because the alcohol was given in a form in which people do not normally take alcohol. This probably does not matter when we are dealing with people who are not alcohol drinkers, but a consistent whisky- drinker is not likely to react normally when he is presented with a concoction of absolute alcohol in orange juice. This is related to the peculiar fact that people appear to acquire a differential tolerance for alcohol, a subject which requires a great deal of further investigation. The other point was that it was hoped that this quantity of alcohol would produce a urine alcohol figure which most authorities would accept as indicating inability to drive a car, a theoretical figure of about three hundred milligrammes of alcohol per one hundred milli- litres of urine. Twenty subjects were taken and they were observed continuously from the moment of taking the alcohol for a period of four hours in all cases and longer in some.

Samples of urine were taken every hour and physical examinations, along the lines of the standard medical examination of " drunken drivers," were made every half hour. In addition to this an examination of the reaction time of the individual was made every half hour. The method of doing this will be dealt with later. The number of subjects may appear to be small, but three considerations apply here. An examination as detailed as this and the in- terpretation of the results is time-consuming, the number of people who are prepared to drink ten ounces of whisky in a short time is surprisingly limited and finally we included a range of types of people of alcoholic experience sufficient, we hoped, to cover all the varying reactions.

T h e general behaviour This was so variable that it rapidly became apparent that no reliance can

be placed on this in estimating alcohol consumption. Our subjects varied from individuals who showed no external sign of the effects of alcohol other than smell, to those who rapidly became semi-comatose and remained so for three to four hours. This was a surprise to us. We knew that a tolerance could be acquired to alcohol, but not to anything like the extent which these experiments showed. Ten ounces of whisky can be a dangerously toxic dose to someone unaccustorrled to alcohol, whereas to a seasoned whisky-drinker i t appears to be little more than an appetiser. An interesting observation was that no one showed any sign of exhilaration or ebullience. There appears to be no doubt that this factor in the effects of alcohol is related to companionship and sur- roundings. The practical importance of this is that when car accidents occur after parties, the party spirit may well be a factor in addition to the alcohol. It may even be a major factor.

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An interesting observation made in connection with general behaviour was the effect of alcohol on the sitting posture. Nearly everyone sits in a pro- gressively slouched attitude as alcoholic intoxication increases. All the subjects also showed speech changes, but many of these were only detectable if the sober style of speech was already well known to the observer.

The standard tests Some of our subjects were unable to perform these satisfactorily, but almost

all those who failed in these tests showed a general behaviour pattern which clearly demonstrated that they were seriously under the influence of alcohol, e.g., those who could not walk along a straight line could not do so because they were unable to walk. Those mentioned above who showed no external sign in their behaviour after consumption of alcohol almost invariably performed the tests satisfactorily. There was no relation between urine alcohol con- centration and the severity of clinical symptoms neglecting extreme cases. All those who consumed the ten ounces of alcohol showed nystagmus a t some time during the subsequent examinations, but the time varies from one individual to another. A selection of results of some tests is shown in Table 1.

TABLE 1 The percentage unable to perform the standard tests correctly a t varying times after con-

sumption of alcohol. Time (Hours) Test 1 Test 2 Test 3 Test 4

Test 1. Standing with eyes closed Test 2. Walking a straight line Test 3. Nystagmus Test 4. Speech defects

The " picking up coins " test appears to have little value. A considerable number of completely sober people fumble the coins. Several variations on the standard tests were also used, e.g., arranging matches in fixed patterns and also the finding of numbers in special patterns. None of these tests, how- ever, showed alterations in performance sufficiently consistent to be of any use in demonstrating the effects of alcohol. In fact several people showed slight improvement a t some of these tests after taking alcohol. Some results of arranging matches are shown in Table 2.

TABLE 2 The time in seconds required for the subjects to arrange eight matches in the form of a

square, related to time after consumption of alcohol.

Time (Hours) Subject 1 Subject 2 Subject 3 Subject 4 Subject 5 0 10 10 9 8 10

Table 3 shows a typical set of numbers in which the subject was asked to find the numbers in one of the series read to him in turn as he finds each one. These sets (Table 4) each require the same effort to find when looked for by scanning each line successively from left to right, using a pointer. Subjects normally

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take one and a half to two minutes to find the series when sober, and two to three minutes when drunk. Some, however, when drunk were able to find the numbers in the normal time, and some improved, e.g., one subject improved from one minute and thirty seconds to one minute and ten seconds. Several sets of numbers and series were used, so that the subject would not learn the placing of the numbers.

TABLE 3 Set of numbers for the co-ordination and concentration test. (Squares are 2 cm. by

2 cm. Numbers 0.7 cm. high)

TABLE 4 Series used with Table 3

Series1 . . . . . . . . . . . . 1 12 20 13 6 21 26 31 32 80 Series2 . . . . . . . . . . . . 23 12 99 73 35 95 79 78 65 98 Series3 . . . . . . . . . . . . 41 15 2 59 71 21 55 27 18 3

Visual motor reaction times

These were taken in two separate ways. To begin with we used an electronic counter which estimated the time taken by the subject to break a circuit by releasing a push button immediately he saw a light come on. This gave results to one hundredth of a second. I t is, however, a relatively complex piece of apparatus which requires a certain amount of maintenance and is expensive. Other methods of timing were considered and we finally produced a machine which is based on timing a falling body. This was first suggested as a method of measuring reaction times, by Robert S. Schwab, in ' Neurology,' Vol. 8, No. 1, 1958. The technique which he used was unsuitable for our purpose, but the principle is the same.

In our model (Fig. 1) a wooden pole is used (a broom handle is suitable). I t is mounted on a back board in such a position that it falls directly and un- impeded through holes in two platforms, which are fixed on the back board slightly more than the breadth of a hand apart. The person being tested is asked to watch the pole and grasp it as soon as he sees it move. The time taken is then read on the scale on the falling pole. The scale is constructed from the formula for estimating distance travelled by a falling body, S = 4 gt2. This method has been tested against the electronic counter, and the results correspond closely. The advantage in cost, simplicity, ease of operation and maintenance are, of course, obvious.

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The reaction times of all individuals were prolonged after the taking of alcohol. The maximum was reached about two hours after ingestion and in most cases there was very little improvement for a further period of half an hour. Tlie

average maximum deterioration was 0.09 seconds, thirty-five per cent. to forty- five per cent. greater than normal, and everyone showed this degree of deterior- ation. Everyone was given a period of trial tests in order to become accustomed to the ' machine ' and then an average of ten results was taken. There is no doubt that prolongation of visual motor reaction time is the most constant detectable sign of physical deterioration caused by alcohol. In some cases the reaction time continued to be delayed for a considerable time after the ' effects ' of alcohol had worn off. This was due to severe nausea. I t is a material factor only in inexperienced drinkers. Table 5 shows a selection of the reaction times found.

TABLE 5 Tlle variation of reaction times in seconds of a selection

time after drinking ten ounces of whisky

Sub- Time (Hours) ject 0 k k 2 1 14 2

1 0.220 0.246 0.260 0.275 0.273 0.283 0.301 2 0.236 0.265 0.280 0.280 0.293 0.315 0.311 3 0.240 0.306 0.297 0.290 0.302 0.319 0.313 4 0.257 0.314 0,301 0.305 0.310 0.347 0.329 5 0.240 0.261 0.283 0.296 0.309 0.292 0.283 6 0.260 0.276 0.293 0.305 0.318 0.344 0.362 7 0.240 0.268 0.276 0.324 0.345 0.340 0.400 8 0.263 0,295 0.318 0.328 0.354 0.350 0.405 9 0.270 0.206 0.324 0.355 0.358 0.350 0.330

10 0.230 0.303 0.362 0.361 0.399 0.401 0.356

of subjects and the relation t o

If a visual motor reaction timer, of the type which we have outlined here, were used in every examination of motorists a t police stations and by Licence Testers, a great deal of valuable information could be accumulated and a figure could probably be established beyond which driving a car should be barred. Special consideration could be given to specific disabilities.

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Urine alcohol levels A great deal of work has been done on urine alcohol, and in the main our

work has mostly confirmed this. Two points are, however, of interest. First, the consumption of a given quantity of alcohol never produces the theoretical maximum figure in the urine. The consumption of ten ounces of whisky is described as the minimum amount to produce a urine alcohol figure of three hundred milligrammes per one hundred millilitres of urine. In fact the highest figure which we obtained from this amount of alcohol was two hundred and six milligrammes. The important corollary from this is that a given urine alcohol figure always represents a consumption of a greater quantity of alcohol than that given as the calculated amount in all the tables and textbooks.

The other point of interest is that previously mentioned, viz., the possibility of there ever being a urine alcohol figure which is prejudicial to the accused, owing to its not being accurately related to the blood alcohol level. This can happen in the falling phase after the lapse of a considerable time since the consumption of the alcohol. We show two typical graphs (Fig. 2) to demonstrate the maximum difference which could occur. Five ounces of whisky were given

" 1 H-URINE RETAINED

E-URINE EXCRETED

Tlnr (hrurr)

Fig. 2

in each case immediately after emptying the bladder. The urine was sampled every half hour by taking part of that voided in the first phase of the experiment and by voiding only one or two millilitres when the urine was being retained. As far as possible, experimental conditions were the same for both series, in- cluding food, drink and exercise. I t will be seen that when the urine is voided frequently, subsequent to the alcohol consumption, the urine alcohol level had returned to a very low value after a period of five hours. If the urine is retained throughout the period the urine alcohol level is still relatively high. This is the point which Defence Counsel sometimes attempt to put forward when cross- examining on the value of urine alcohol examinations and it is the basis for the suggestion that the bladder should always be emptied prior to the taking of the actual test sample. There is, therefore, this theoretical possibility of ' error.' In practice, however, it does not appear to us to be of importance. Two factors are operative here : first, the discrepancy is not sufficient to be discriminatory against the motorist except under the most exceptional conditions ; second, people just do not retain their urine for periods of four to five hours after the consumption of alcohol. Apart from an exceptional circumstance, we consider

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that the testing of urine alcohol levels is a reliable method of estimating alcohol consumption. This is important because it is probably the simplest reliable test available. Blood alcohol levels would, of course, be better, but i t does not appear that they are likely to be made generally available to examiners in this country.

I.. LLACnON TIHE

C U R M L IICOHOL

Fig. 3

We show graphs (Fig. 3) demonstrating the relationship between urine alcohol levels and reaction times after the consumption of ten ounces of whisky. I t will be noted that the deterioration in visual motor reaction time corresponds closely with the increase in urine alcohol level. There is a slight lag in the return to normal just after the peak in the reaction time graph, and this is probably due to exhaustion effects.

Saliva alcohol levels We also examined the lcvel of the saliva alcoliol a t thc same time as the urine

was examined. In the main this gave accurate results, but there are factors which make this test unsuitable for legal purposes. For instance, regurgitation from the stomach frequently occurs.

The present situation with regard to alcohol and the motorist We consider that this is unsatisfactory. We have already spoken about the

different standards applied by different doctors. Unfortunately, there are also very different standards applied by judges. This is well known to defending !awyers and frequently adjustments of various kinds are made in order to changt: the hearing of the case from one judge to another. I t has also been suggested that in England juries apply very different standards from judges. The authors have no personal experience of this, but there appears to be some statistical confirmation of the idea. Nobody is really to blame for the vagaries in the application of Section 6 of the Road Traffic Act, 1960. The difficulty arises from the expression " proper " control of a motor vehicle. What is the degree of control of a vehicle which is proper ? How much of a person's normal control can be lost before he ceases to have proper control ? Everyone answers these questions from a personal standard not from an absolute standard. Boswell, writing of the Judges of the Court of Session of his day and discussing suggestions that they were sometimes sensitive to influences other than the facts of the case,

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said, " A n d i t must be owned that of the m a n y cases that come before the Court of Session there i s a good ~ r o ~ o r t i o n such as the Judges will differ upon merely i n in cool opinion." No wonder then that regard casts the balance without their knowing it. This may have been true of the judges in Boswell's time, it is certainly true of everyone concerned with the interpretation of Section 6 cases to-day.

Whilst there are reasonable explanations for the discrepancies in the ap- plication of the law, this does not make the situation any more tolerable. Nothing makes law quite so ineffective as uncertainty in its application. The history of the law attempting to control ' drunken drivers ' certainly demonstrates its ineffectiveness.

What should be done ? There are two possibilities. Pay no attention to the alcoholic factor and concentrate only on bad driving.

This sounds revolutionary, but it is by far the most logical way of dealing with the situation. I t is bad driving which is the danger and it matters not whether it is due to alcohol, drugs, bravado, bad temper, fatigue, disease, physical in- competence or old age. People who drive badly because of any of these reasons must be stopped driving for such period as will deter them from repeating the offence and will deter others from committing these errors. Where the defect is irreparable the person must be stopped driving permanently. This is the best solution, but it would require a degree of interference with the ' liberty ' of the subject which is tolerated in this country only in times of war. I t could, however, be operated, and, as cars increase in speed and the roads become more congested it may be forced upon us. I t is, however, at present impracticable in the sense that too many would not accept it and because of this we put forward a second suggestion, which is :-

As far as drunken driving is the factor at issue, the Courts should decide the matter on a urine alcohol figure and on this alone. This would provide law which would be certain, would be known to all, and would not be dependent on personal interpretations of judges and doctors.

If this principle is accepted the problem is to decide at what level the urine alcohol should be set with which it is illegal to drive a car. We have given a great deal of consideration to this and think that it should be any figure in excess of one hundred milligrammes of alcohol per one hundred millilitres of urine. The difficulty is to find a figure that will ' catch ' almost everyone whose driving might be appreciably impaired by alcohol and yet not interfere unreasonably with the pleasures of the community. This is much more difficult than might be imagined. Some of the most dangerous driving which we have seen has been by young men who have had one or two drinks and then set out to show a companion, usually a female, the magnificent control which they have of a high-speed vehicle. The alcohol in these cases is definitely a factor, but it is so intangible that it cannot be shown in any physical examination and in fact can hardly be demonstrated by scientific tests as the amount will probably fall within the experimental error of the method. On the other hand there is the middle-aged gentleman driving back from his club with a urine alcohol level of around three hundred milligrammes per one hundred millilitres of urine, aware of his condition and driving not recklessly, but with exaggerated caution. These men rarely have accidents once they have negotiated the club car park. Between these types there is an endless variety. How, for instance, do we compare the driver who has normally one hundred per cent. driving capacity and is twenty per cent. impaired through alcohol with the man who has normally eighty per cent. driving capacity and is ten per cent. impaired through alcohol ? The urine alcohol figure of one hundred milligrammes per one hundred milli- litres of urine seems to us the best figure which can be used. This will catch almost all the drunken drivers who would be detectable by any examination and it will allow a reasonable use of alcohol.

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These urine alcohol figures do not sometimes convey very much to the practising doctor, and less to the layman. I t may help people to understand these things better if we gave some examples. If you weigh about twelve stones, go to a dinner party, start the evening about 8 p.m. and have three fairly large sherries before dinner, three glasses of wine at dinner, and an average liqueur after dinner, then if you are driving home about twelve midnight you will have a urine alcohol of about eighty milligrammes per one hundred milli- litres of urine. If, on the other hand, you go to a pub at 7-45 p.m. and drink fairly steadily for two hours, you will probably drink five small whiskies and nine beers (four and a half pints), and by 10-15 p.m. have a urine alcohol level of two hundred and thirty milligrammes per one hundred millilitres of urine. These are two actual drinking 'incidents' and are typical examples of two fairly common types of drinking. If the bladder is full when these drinking spells start and the urine is retained throughout, then a considerably lower urine alcohol level will result. Five ounces of whisky under these circumstances may produce a maximum urine alcohol figure of thirty milligrammes per one hundred millilitres of urine. We have done this for experimental purposes, but it produces such discomfort that there is no possibility of its occurrence during ordinary drinking sessions.

We must recognise that there are many people who can drive a motor car safely with a urine alcohol figure well beyond one hundred milligrammes per one hundred millilitres of urine. This has been the finding of all examiners who have any considerable experience of relating alcohol urine levels to behaviour and was given striking scientific experimental corroboration by the previously mentioned M.R.C. Memorandum, No. 38. The setting of the above figure as a limit does penalise these people, but it seems to be a penalty which they must pay in the interests of the community, and we think that this will be accepted by them provided the situation is made clear.

There is at the present time a belief that alcohol is a major factor in the causation of road accidents. The authors of this article believe that the alcohol factor has been somewhat exaggerated. The time for beliefs in this matter is now past. I t is time to put the affair to a practical test and the method which we have outlined above is the simplest method of doing this.

We would like to record our gratitude to Professor John Glaister and Dr. J. M. A. Lenihan for advice and use of equipment. We are also indebted to the Commissioners of Customs and Excise.