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Direct arterial pressure and electrocardiogram have been measured continuously over a period of 24 hours in 15 patients. Observations have been made on the behaviour of these variables during 30 separate episodes of motor car driving. The patients were divided into three groups: (1) five normotensive subjects, (2) five patients with essential hypertension who were not receiving therapy, and (3) five patients with angina pectoris who were either normotensive or hypertensive.In all but one subject, apart from variable changes in heart rate, no significant arrhythmias or S-T segment changes were observed in the electrocardiogram. The arterial pressure remained remarkably stable throughout the driving period in all three groups and there was no significant difference between the levels of blood pressure at the beginning and end of a journey. There were short periods of raised arterial pressure during driving related to such episodes as overtaking, but these quickly returned to baseline levels. Two patients experienced anginal pain during driving.It is concluded that motor car driving does not have such a pronounced effect on the blood pressure as might have been thought.

A total of 100 outpatients in the North-East of Scotland were given a simple anaesthetic of propanidid, nitrous oxide, oxygen, and halothane. The study was undertaken to assess what happened to patients when they left hospital after outpatient surgery. An outpatient questionnaire was used, and results show that 31% of patients journeyed home unaccompanied by a responsible person, 73% of car owners drove within 24 hours of the operation, and 9% drove themselves home. Postoperative symptoms of drowsiness (26%), headache (27%), nausea (22%), and dizziness (11%) were recorded, and a higher incidence of symptoms was recorded when surgery exceeded 15 minutes. A new form for outpatient operative procedures in Aberdeen has been devised with modern legal implications in mind.

A double-blind controlled comparison of four commonly-used tranquillizing drugs (haloperidol, amylobarbitone sodium, chlordiazepoxide, and trifluoperazine) against placebo was made in their effects on the performance of volunteers during three low speed vehicle-handling tests. The drugs (with the exception of haloperidol) significantly altered driving behaviour though they did not seem to interact significantly with alcohol. There is, therefore, a strong possibility that such drugs will similarly alter driving performance in patients taking them for therapeutic purposes. Since, as these experiments also show, those affected may be subjectively unaware of it, and routine clinical screening is not sensitive enough to detect them, physicians should warn patients of the probability that their driving performance will be affected by such drugs, particularly during the first few days that they are taken.

The status of the epileptic applicant for a licence to drive a private motor vehicle has changed from total prohibition through a stage of partial approval subject to medical assessment to the present conditional right to a driving licence. We report a study of a series of patients which shows that many and probably most epileptics have obtained driving licences by concealment of their condition, yet the new regulations continue to expect true declarations. It is suggested that, in common with applicants for a public service vehicle or a heavy goods vehicle driving licence, the applicant for a licence to drive a private motor vehicle should provide a medical report of fitness. The epileptic should be included in a general category of medically restricted drivers subject to individual medical assessment.

Electrocardiograms were recorded in experienced motor-car drivers accustomed to busy city traffic while driving their own cars along familiar routes. The majority with normal hearts or a history of coronary heart disease increased their heart rates; brief periods when the rate exceeded 140/min. were recorded in both groups. ST changes not caused by tachycardia developed in 3 out of 32 normal drivers. Of 24 drivers with coronary heart disease 13 increased their ST and T abnormalities, the changes being gross in six. A further five developed multiple ventricular ectopic beats. Two coronary drivers experienced anginal pain and two left ventricular failure. Healthy motor-racing drivers increased their heart rates to 180/min. in the few minutes before the start of a race and to above 200/min. while racing.Little or no change in the plasma catecholamine levels was noted in three coronary subjects immediately after a city drive compared with resting levels. All the racing drivers showed a considerable increase in noradrenaline, and in one instance adrenaline, immediately after racing.Persons in whom angina is easily provoked when driving or who are in borderline left ventricular failure should be advised not to drive.

The idea was suggested by the author previously (Bull. Math. Biophysics,22, 257–262, 1962) that the keeping of the car close to the center of the lane is a problem of psychophysical discrimination between two conflicting stimuli, namely a stimulus to turn away from the left, resp. right edge of the lane. This is elaborated in the present paper. The effects of discrimination threshold and of the endogenous fluctuations which result in erroneous judgments are discussed. In order that driving should be possible at all, a relation, derived in this paper, must hold between the threshold of discriminationh, the sensitivity coefficientb of the driver to changes in the distance between the car and the edge of the lane, and the width of the lane. General expressions are derived which characterize the stochastic nature of the tracking curve.

In a previous paper (Rashevsky, 1959,Bull. Math. Biophysics,21, 299–308) we derived an approximate expression for the maximal speed of driving in terms of the reaction time of the driver. In the present paper the possible effects of unevennesses of the pavement, of such distracting stimuli as road signs etc. on the reaction time are studied theoretically, using previous developments of the mathematical biophysics of the central nervous system. In this manner expressions are derived which determine the maximal safe speed in terms of road conditions and other distracting stimuli. Effects of those conditions on fatigue are also discussed.

The incidence of 'alcoholism' is difficult to determine. This difficulty reflects the absence of a universally accepted definition of the disease. Various attempts have been made to base inter national comparisons upon such indices as alcohol consumption per person, death rates from 'alcohol related' diseases, hospital admission rates for 'alcoholism', and even conviction rates for 'drunk enness'. No problem would arise if all of these yardsticks displayed a high and consistent inter correlation, between regions and over time. In fact the widely used Jellinek formula assumes this to be the case and, although this method of comparing the incidence of alcoholism internationally has been criticized (Sundby, 1967), its use has influenced numerous discussions of national levels of alco holism. The present paper has been prompted by the authors' knowledge of the Irish scene. In view of the prominence of the emigrant Irish in several studies of alcoholism, the case of the Irish in Ireland deserves more attention than it has received, especially since (as is argued in the course of the present paper) it calls into question the feasibility of developing any consistent indices of the incidence of alcoholism. Some aspects of this topic have already been discussed among research workers in Ireland (Lynn and Hampson, 1970; Walsh, 1970). Literary and historical sources provide abundant evidence that the Irish have long been regarded as exceptional in their abuse of alcohol. Commen tators have been virtually unanimous in applying the stereotype of the drunken Irishman. A syste matic discussion of the literary and anthropological evidence, together with an attempt to provide a theory of Irish alcoholism, have been provided by Bales (1962). This paper attempts to compare the Irish case with as large a number of other countries as is feasible, using quantifiable indices that have been proposed by various authors as possible yardsticks of the prevalence or incidence of alcoholism. In this way it is hoped not only to place the Irish case in perspective but also to evaluate the reliability of these yardsticks in international comparisons of alcoholism. The measures that will be considered are

In connection with a series of previous papers by this author (Bulletin of Mathematical Biophysics,21, 299–308, 375–385;22, 257–262, 263–267;23, 19–29;24, 319–325) results obtained by A. Crawford (Economics 5, 417–428) on the effects of irrelevant lights on reaction times toward a given light stimulus are discussed. The conclusions from a previous paper of this author (Bulletin of Mathematical Biophysics,23, 19–29) are elaborated.

This volume contains 21 papers and seven theses. In the opening paper Merriam described the effect of radiation on cataract production. Adequate time-dose relationship was observed to give a slope that was expected when compared to known tissues. This presentation was followed by a delightful essay on "The Creation of Eve" (Veronese) by Karl Ascher. Byrnes reported on his studies of the visual factors involved in automobile driving. He suggested that driving licenses should be based upon daylight operating, with additional permits required for night driving given or withheld. Birge spoke on pseudoglaucoma which he defined as "false, deceptive, or deceitful glaucoma." Scheie reported further on his favorable experiences with peripheral iridectomy combined with scleral cautery. His series included 57 eyes with infantile glaucoma and 15 eyes with juvenile glaucoma. Maumenee reported further on the pathogenesis of congenital glaucoma, adding 11 eyes of six patients to his list. After a

The automotive vehicle has become one of modern Society's deadliest killers, in addition to injuring thousands of lives every year. This paper describes a combined accelerator and brake in one pedal which may be a technique for reducing automotive accidents. Its use is riot limited to automobiles, but can be used in any typo of automotive vehicle. Reaction time, from onset of an accident stimulus until the brakes are initially applied, is 0-256 seconds with this one pedal system, versus 0.468 seconds under the conventional two pedal accelerator-brake system. This saving of over 45 per cent in reaction time, results in the brakes of a vehicle being applied about 19 feet earlier at 60 mph for example. In addition, the driver would have this much more room to swerve and possibly avoid an otherwise serious situation ahead.

The problem of fatigue in driving is two-fold. It includes both the fatigue resulting from driving and the effects of fatigue, from whatever source, on driving. The study of fatigue in drivers is hindered by the fact that no reliable method of measuring fatigue or defining driving performance has yet been found. This paper reviews some of the research on operational fatigue, and discusses the source of fatigue in driving. It is concluded that stress is an important factor in the production of driving fatigue, and various methods of assessing the effects of the emotional arousal it produces are discussed.

In a previous communication we reported data supporting the recommendation that a red road traffic signal should have an intensity of 200 cd for optimum recognition from 100 m when the signal is seen against a very bright sky (104cd/m2). This confirmed the earlier result of Boisson and Pagès. The present paper extends the data to include (a) the effect of signal size on optimum signal intensity for a practical range of angular diameters (4.1 to 16.5 min of arc), and (b) the effect of background luminance for a range of luminances of 1.5 ft-L to 2250 ft-L. The results show that optimum signal intensity is independent of signal size and that spatial summation by the visual system is complete. However the same data demonstrate a failure of spatial summation when a conventional threshold criterion (probability of seeing the signal 0.5) is used. It is shown that smaller signals will be more effective than larger ones of the same intensity if their intensity is less than optimum. Optimum signal intensity is shown to be a linear function of background luminances greater than 10 ft-L. A graph relating optimum signal intensity to signalling range for various background luminances summarises the experimental data.

This paper describes the design and use of a portable, fully adjustable steering device, capable of being fitted to the steering wheel of converted and subsequently abandoned vehicles. Such vehicles may then be driven without destroying fingerprint evidence on the steering wheel. The work was done at the request of the New Zealand Police Department.

THIS PAPER REPORTS THREE POTENTIALLY DANGEROUS EPISODES OF VISUAL DISTURBANCES THAT OCCURRED IN HALLUCINOGENIC DRUG USERS WHILE DRIVING. EACH DRIVER ACTED ON HIS PERCEPTIONS, AND ONLY AFTER HE HAD CHANGED THE COURSE OF HIS AUTOMOBILE DID HE REALIZE THAT WHAT HE HAD SEEN WAS UNREAL. EACH PERSON WAS CERTAIN HE WAS IN AN UNDRUGGED CONDITION AT THE TIME. THE AUTHOR CONCLUDES THAT THE USE OF HALLUCINOGENS MAY BE INTRODUCEING A NEW DRIVING HAZARD THROUGH THEIR ABILITY TO CAUSE VISUAL DISTURBANCES AND SPONTANEOUS RECURRANCES OF ACUTE EFFECTS. /SRIS/

The driver tries to keep the car in the center of the lane. If the car is too near the left edge, this causes the driver to make a “corrective” right turn. If the car is near the right edge, a “corrective” left turn is made. Therefore, a quantity which decreases with increasing distance ΔL from the left edge may be considered as a stimulusSR producing the reactionRR of turning to the right. A similar situation holds for the distance ΔR from the right edge. When the car is in the center of the lane, ΔL = ΔR andSR=SL, the stimuli are equal. We thus have here a situation analogous to the one studied by H. D. Landahl in his theory of psychophysical discrimination. In general a reactionRR (resp.RL) will occur only ifRR−RL≥h* (resp.RL−RR≥h*) whereh* is a threshold. Applying Landahl’s theory to this situation, we find thath* determines the distance from the edge, at which a corrective turn is made. This distance is not constant, but a function of the speedv of the car. The requirement that a corrective turn should be madebeforre the car runs off the road leads to an expression for the maximum safe speed. Because of the transcendency of the equations involved, closed solutions cannot be obtained. It is, however, shown that the expression for maximum safe speed, given in a previous paper (Bull. Math. Biophysics,21, 299–308, 1959), is a rough first approximation to the expressions found now.

The use of breath-analysing equipment is now written into much legislation throughout the world. In Australia the type of equipment used is the "Breathalyzer", a brand that has special advantages because of several unique features. This legislation is part of an international attempt to reduce the growing road-toll epidemic, but itself involves many problems. The public right to use the traffic system with safety must be balanced against the individual's right to question in court a charge, essentially one of drunken driving, made against him. "Breathalyzer" legislation tends to make for automatic punishment based on arbitrary standards, and mandatory penalties which often violate the old principle that guilt is not absolute, but has its degrees. Breath-analysing equipment measures blood-alcohol levels (BAL's) only indirectly; if "Breathalyzer" legislation is based on the view that driver-failure is related to a specific minimum BAL, then it should be framed in such a manner as to ensure that there is a negligible chance of an accused person being unjustly found guilty. This may happen because of a discrepancy between breath-alcohol and blood-alcohol levels. Comparative studies in Australia, as well as in other countries, show that "Breathalyzer" readings tend on an average to be lower than the blood-alcohol concentration recorded directly from a specimen of blood taken from a vein in the arm. The usual under-estimation is about 10 mg/100 ml (0.01% BAL), but an occasional over-estimate has been recorded, in one case as much as 28 mg/100 ml (Preston, 1969). In this paper, various aspects of this problem are discussed and some desirable modifications of "Breathalyzer" legislation are suggested.