Timothy Paul Hutchinson

VEHICLE MASS AND DRIVER INJURY

This paper analyses the effect of vehicle mass on the severity of injury sustained by drivers in head-on accidents in rural areas of Great Britain In two-vehicle collisions, a consequence of Newtons laws is that relative velocity change is in inverse proportion to vehicle mass. Increased velocity change causes increased severity of injury. Our data show, for instance, that when the larger vehicle is twice the mass of the other, the percentage of deaths in the lighter vehicle is about six times that in the heavier The effect of mass alone on driver injury has also been investigated—by considering only those two-vehicle collisions in which the vehicles were of nearly equal mass—and found to be negligible.

Factors affecting the times till death of pedestrians killed in road accidents

Police reports of fatal pedestrian road accidents in London in 1970-71 have been examined, and the times of death extracted. These have been related to estimated speed of impact, age of injured person and type of striking vehicle. High-impact speed tends to lead to quick death. Age has no statistically significant effect once speed is allowed for, but because a greater proportion of elderly pedestrians are killed by slowly moving vehicles, the elderly on average die later than the young when all speed groups are combined. Type of vehicle also influences time of death, with motor cycles giving rise to later deaths and heavy goods vehicles to quicker ones than do cars.

The definition of restraint effectiveness

Abstract When calculating the effectiveness of an injury-reducing device from data on injuries with and without the device in operation, one meets the difficulty that injury is merely graded into a few categories from none to fatal, not measured on a continuous scale. This paper discusses the derivation of formulae that overcome this, and of statistical tests for whether the device has any effect. It is shown that there are two important issues to be considered when deciding on a formula: (i) The distinction between effectiveness relative to (a) the total variability in injury severity in all accidents, or (b) the variability within the particular circumstances of an individual accident, (ii) The shape of the probability distributions of injury severity in the two circumstances, with and without the device. As to the first issue, effectiveness of type (b) requires each case with the device to be matched with a case without the device, whereas type (a) does not; type (b) leads to a more powerful statistical test, whereas type (a) is more suitable for descriptive purposes. As to the second issue, it is shown that the logistic distribution has suitable theoretical properties and leads to formulae and statistical tests that are conveniently simple. However, it is demonstrated that formulae that are linear in the probabilities are unlikely to be suitable.

An easy method of calculating approximate recurrence risks using a multifactorial model of disease transmission

In the usual form of the multifactorial model of disease transmission, calculation of recurrence risks is made difficult by the necessity to evaluate integrals involving the Normal distribution. It is suggested here that this becomes much easier if the Normal distribution is replaced by the Pareto distribution. Tables are given systematically comparing values of recurrence risk calculated on the Normal and Pareto models when information about two or three first degree relatives is available. Also, a more complicated pedigree is examined. It is shown from these comparisons that the Pareto model gives very similar results to the Normal model.

Approximating a trivariate Normal probability that is of special relevance to the multifactorial model of disease transmission

A study has been made of methods of approximating the probability of severe disease occurrence in the child of parents who both suffer from a mild (or subclinical) form of the disease in question. A wide range of parameter values has been considered. It has been found that

Recent trends in traffic injury

Data in the Registrar-Generals statistical reviews for 1958-75 and in the reports of the Hospital In-Patient Enquiry for 1964-73 have been examined to ascertain the light they shed on the changes in the patterns of injury from road accidents over this period. Causes of death, primary injury for hospital inpatients and average length of hospital stay have been examined. It seems that an increasing proportion of deaths are being ascribed to internal injuries and a decreasing proportion to fracture of the skull.

Witnesses' estimates of the speeds of traffic accidents

Abstract Using as data base the fatal pedestrian accidents occurring in London in 1970–1971, the usefulness of police reports for estimating the speeds of road traffic accidents was investigated. Two approaches were used: correlating estimates by different people of the initial speeds, and relating vehicle damage to estimated impact speed. The first approach established quite high correlations (around 0.6) between different estimates, and in the second a positive association was found between speed and damage. Furthermore, the average difference between estimates made by independent witnesses and by the drivers of the vehicles involved was small (3 m.p.h.). In addition, a table is given showing the distribution of estimated impact speeds for this sample of accidents.

Determination of patterns of human body measurements by use of partial correlations

From an anthropometric survey of British car drivers, matrices of correlations between body measurements have been obtained for males and females. These correlations have then been transformed into partial correlations with age, stature, and weight successively eliminated. It is argued that this process reveals patterns of body shape without the need for the complexities of more sophisticated techniques such as factor analysis.

Partial Knowledge and the Theoretical Basis of Linear Corrections for Guessing.

Abstract In scoring multiple-choice tests, a score of 1 is given to right answers, 0 to unanswered questions, and some negative score to wrong answers. This paper discusses the relation of this negative score to the assumption made about the partial knowledge which the subjects may have available.