Lesson 15Injuries are classified according to the following criteria.1. Slight injury. An injury of a minor character such as a sprain, bruise or a cut or laceration not judged to be severed.2. Serious injury. An injury for which a person is detained in hospital as an inpatient, or any of the following injuries regardless of whether he is detained in hospital: fractures, concussion, internal injuries, crushing’s, severe cuts and lacerations, severe general shock requiring medical treatment.3. Death. Death within 30 days.Although not in general used for compiling national statistics, an alternative scale for classifying injury is used for research purposes, in which injuries are usually divided into seven levels.事故被定级取决于以下几个标准（1）轻伤。
较轻的伤害比如扭伤，擦伤，割伤，划破等不能被判定为严重的伤害。
（2）严重的伤害。
一个人必须被留在医院进行入院治疗的伤害或者不管其是否住院，只要有以下伤害情形之一的，骨折，脑震荡，内伤，压伤，严重的割伤，严重的休克需要医学治疗。
（3）死亡。
30天内死亡。
另一种伤害分类方法一般不用作汇编国内统计资料，但被用于研究目的，该方法把伤害分为七个等级。
以下是简写的伤害分类等级。
等级0：没有伤害。
等级1：轻伤。
等级2：中等伤害。
等级3：严重伤害，没有生命危险。
等级4：严重伤害，有生命危险。
等级5：危险的，不一定幸存。
等级6：死亡。
Details of injuries falling into these categories for the different regions of the body are given in the reference paper. Alterations are made to these scales from time to time.在该引用中详细的伤害因身体部位的不同被分为以下几个种类。
分类方法也时时刻刻在改变。
Since injury accidents are the only ones which are nationally rec orded and analyzed, there statistics underestimate the true numbers o f accidents, because accidents which do not result in injury are not included (although a small proportion of these accidents are reported to the police). Intuitively it might be thought that all damage-only accidents were so trivial and occurred at such a low speed that they were not worth considering. That this is not so is perhaps best illu strated by an example.由于伤害事故时唯一被全国记录并分析，这些统计低估了真正的事故数，因为那些没有造成伤害的事故并没有被包含（尽管一小部分事故被告知了警察）。
直观上所有发生在低速情况下仅仅造成损害的事故是如此不重要并不值得被考虑。
也许举一个例子说明事实并非如此。
Consider what happens when a car carrying a driver alone strikes a rigid wall head on at a sped of, say 25 mile/h.Not every such accide nt results in injury. At any particular impact speed there is a probability of being uninjured, slightly injured; seriously injured or killed, and of cour se, the probabilities of injury increase with impact speed and those of be ing uninjured decrease. When no injury results such accidents are not in cluded in the national statistics, although other accidents at the same sp eed but in which the driver is injured are included.假如一辆载有一名驾驶员的轿车以每小时25英里的速度迎面撞上一堵硬墙，我们看看会发生什么。
并非每起此类事故都会造成人员受伤。
以任何速度撞击都有可能造成无人受伤、有人轻伤甚至有人重伤和死亡的可能，当然了，随着撞击速度的增大，人员受伤的可能性也会相应增加，而无人受伤的可能性则会相应减小。
此次全国统计数字并未包括此类事故中无人受伤的结果，但是包括了撞击速度相同并造成驾驶员受伤的其他事故。
In similar circumstances, if there are two or more people in the car. The chances of an injury accident are, of course, greater than if there is only one occupant. In general, the greater the number of people involved in an accident of a given severity (in this case severity is measured by speed of impact with a wall.) the great the chance of it being an injury accident, and therefore of being included in the national statistics.在相似的情况下，如果有两个或者以上的人在车内，伤害发生的机率比一个人要大。
一般而言，在一个具有一定严重程度的事故中（这里严重程度以撞墙速度的结果衡量）所涉及的人数越多该事故成为伤害事故的概率越大，因此该事故被包含进国家统计资料的概率越大。
Thus head-on collisions between cars are more likely to be recorded than accident in which only one car is involved. Moreover, of the accident is of a kind in which the risk of injury is low, such as read-end collisions betweens cars. The proportion of such accidents which appears in the national statistic is lower than for high risk accidents such as head-on collisions ,or collisions with heavy commercial vehicles ,and all types of accidents in build-up areas where speeds are low are likely to have a lower proportion of in injury accidents than those in rural areas ,where speeds are higher .相比那些仅涉及一辆车的事故，这些正面碰撞的车辆事故更容易被记录。
此外，如果事故是低伤害风险的，比如追尾，这类事故相对于那些高危险的事故比如正面碰撞，出现在国家统计资料上的可能性是很低的。
各种发生在建筑多的低速度地区的事故可能有低的伤害比例比那些发生在高速度的乡村地区的事故。
There features of the national statistics should be remembered when making use of accident data.当利用事故数据时，这些全国统计资料的特征应当被记录。
2国际比较Table 15.1 compares the fatalities in Great Britain with those in seven otherscountries and will be seen that, whether judged by deaths per unit of population, or by deaths per vehicle, Britain compares favorably with almost all others except Sweden. 表15.1比较了英国的公路死亡数和其他七个国家的情况。
它表明无论按人口或者单位事故的死亡率，英国都比除了瑞典之外的国家有利。
Misleading conclusions may be drawn if only one of the rates, deaths per vehicle ,or deaths unit population ,is considered .For example, on the basis of deaths per 100000 populations both the Irish Republic and Spain have lower figures than the US , while on the basis of deaths per vehicle ,the reserve is true. It was shown some years ago that these contradictions arise because those countries with large numbers of vehicle per unit of population usually have large numbers of deaths per unit of population but small numbers of deaths per vehicle, perhaps because, as vehicle become more numerous, road users become more careful and road conscious. By comparing numbers of deaths from 1930 to 1950 in 18 countries, it was shown that there was an approximate relationship between deaths per annum 100000 population ,D/p ,and N/p the numbers of vehicles per 1000population, represented mathematically by D/p= 0.0003(N/p). Alternatively, the number of deaths per annum D =0.0003(n/p). In later work, covering 70 countries, from 1960 to 1967, the same relationship was found to hold.如果仅仅按一种比率，单位事故死亡率或者单位人口死亡率，它将描绘出令人迷惑的结论。