麻仓优 人鬼殊途番号:汽车进化得越来越快：人类却没有

2011年10月11日 14:52 作者 弗兰克·迈金纳

Whenever a speed limit change is proposed there is a good deal of public debate. The British government's recent call to allow drivers to do 80 miles per hour (129 kilometres per hour) on some of the country's fastest roads, instead of the current 70mph (113kph), is no different.

汽车限速规定的改变总能够引起一阵轩然的讨论。英国政府最近宣布的把境内某些公路的最高时限从70英里每小时（113公里每小时）提高到80英里每小时（129公里每小时），同样引起了舆论的关注。

Should we raise the speed limit to take advantage of the greater capabilities of modern vehicles? Would this increase casualties? How should limits be enforced? These are just a few of the questions that provoke endless debate. Speed is not the only factor in crashes – no one would argue otherwise. However, its importance for public health is that it is easily experimented on. Contrast that with driving while tired, which is less easy to measure and change. 

我们是否应该提高时限让新型汽车的能力得以最大化？这么做是否会增加事故伤亡人数？新时限应如何施行？这只是无休无止的争辩中的几个问题。大家都承认——速度不是事故的唯一因素。但是它是容易检控的因素，因而对公共安全意义重大。相反，像疲劳驾驶这样的因素则不容易检控。

There is no doubt that over the past 30 years vehicles have evolved to go faster with consummate ease. Before taking full advantage of this we might consider whether we, the drivers, have evolved much over the same period. Unfortunately our reaction times are not any faster, nor are our bodies any better at withstanding the forces involved in a crash.

毫无疑问，在过去的30年里汽车已经被改造得更快、更便于操作。在享受这一切之前，我们或许可以反思，作为司机的我们是否也跟着改进了呢？事实上我们的反应速度并没有提升得更快，我们的身体对事故的耐受力也没有增加。

A human who tries really hard can sprint at about 30kph. To reach even that speed, we have to put lots of energy into the system, our heart is pumping, we have the wind in our face and massive experience of movement – in other words, we have overwhelming biological feedback to tell us just how fast we are going.

Velocity blindness

When we drive a car, however, the energy input is the small movement of a large toe. The output, in contrast, is that we can easily travel at more than four times the maximum speed for which we have been designed – and with almost no experience of movement. The feedback to the brain from the legs, heart and lungs when we are driving is effectively that of no movement. Add to that the fact that prolonged exposure to speed reduces perceived velocity and that speed cues such as engine noise are systematically eliminated in modern vehicles, and it is no wonder there are some challenges in obeying limits.

速度盲区

We have the speedometer, of course, but this hardly provides visceral feedback – and, bizarrely, about half of the dial is devoted to illegal speeds. It is rare for any other product to broadcast its illegal capabilities like this.

我们还有速度仪表，但它极少反馈危险信息——而且，怪异的是，它几乎有半个表面都是显示超速速度。很难想象有什么其他物件如此张扬自己的违法能力。

For years, the general message from governments has been that, for safety reasons, a reduction in speed is good because it reduces casualties. But this has been difficult to get across. Messages such as "at 35mph you are twice as likely to kill someone as at 30mph" may be hard to appreciate if you assume that energy increases linearly with speed – in fact, it rises with the square of the velocity.

近年来政府一致认为限速有助于安全因为它能够减少伤亡。但限速的法令并不那么容易通过。如果你觉得耗油率和速度是成正比的，那么“把时速从30英里增加到35英里，你致人死亡的几率就会翻倍”这样的信息根本就是耳边风，事实上，耗油率是按速度的平方来增长的。

The transfer of that energy to the human body is the problem. The evidence on the relationship between speed and casualties is unambiguous whichever way it is examined. For example, raising the 55mph (89kph) speed limit to 65mph (105kph) in the US was estimated to have increased fatalities by 15 per cent. 

Survival speeds

Different types of road have different functions: access roads, which border residential and shopping areas; distribution roads, which need more entry and exit points; and through roads such as freeways and motorways which are for uninterrupted movement, with limited entry and exit.

保命速度

不同的路有不同的功能：普通公路连接了居民区和商业区，快捷干道有着更多的入口和出口，联运路，例如高速干道，要畅通无阻，因此有着很少的进出口。

Survivability refers to the body's capacity to tolerate the energy transfer in accidents. Evidence shows that on access roads, where crashes involving pedestrians are likely, a 20mph (30kph) limit is appropriate. On distribution roads, where side impacts are likely – when a car might ram into the side of another that is pulling out of a side road, for instance – the limit should be 30mph (50kph). In situations without pedestrians and where side impacts and head-on collisions are improbable – motorways and freeways – the limit should be 60 to 70mph (100 to 110kph).

 生存可能性是指身体在意外事故中承受能量转移的能力。有迹象表明在很易与行人发生冲撞的普通公路上，低于时速20英里（30千米）是很合适的。在容易发生侧面碰撞的快捷干道上，汽车很容易冲撞到正从岔路口进入的车辆，在这样的路上时速应低于30英里（50千米）。在没有行人也不可能有正面冲撞的高速干道上，时速不高于70英里（100千米到110千米）是可行的。

Getting drivers to stick to limits, be they new or old ones, is another thing. Deterrence is an obvious route. Deterrence theory, derived from the work of the 18th-century judicial theorist Cesare Beccaria and the 19th-century philosopher and social reformer Jeremy Bentham, emphasises the certainty, severity and imminence of punishment. The certainty of punishment has the clearest deterrent effect, which is problematic for speed enforcement because it relies on an uncertain police presence.

 比这更难的是让司机们，不论新手还是老司机，遵守限速。普遍的做法就是威慑。威慑理论源于18实际法理学家切撒雷·贝卡利亚(Cesara Beccaria) 和19世纪哲学家、社会改革家杰里米·边沁，他们强调了惩罚必须是必行、严格和当时的。必行对制止具有最明显的效果，但要实施在超速这个问题上却是困难重重，因为检查超速需要恰逢警察在场。

This can be solved by speed cameras, which have themselves stimulated a good deal of media debate. Controversy has focused on whether their goal is safety or revenue generation. Policy-makers can tackle this by emphasising casualty reduction: for instance, they can place cameras at accident locations, allocate fines to road safety, advertise the accident location by highly visible cameras and prior warning signs, and offer education for first-time offenders.

 测速相机可以帮助解决这个问题，尽管他们已经引起了许多媒体舆论。争执的焦点集中在设立这些测速相机的目的到底在于确保安全还是为了“创收”。当权者可以展示交通伤亡减少的事实来减少质疑，例如，在事故多发地段安置测速相机，对超速车辆罚款，通过明显的测速相机装置和警示牌来提示事故多发点，还有向初犯提供教育。

It may be important for politicians to distinguish between media debate and public concern on this issue. For example, Damian Poulter – a colleague at the University of Reading, UK – and I examined the UK government's British Crime Survey to determine what people are concerned about in their local communities. In comparison with a range of antisocial behaviours such as race attack, drugs, intimidation and noisy neighbours, speeding was the top concern (Accident Analysis and Prevention, DOI: 10.1016/j.aap.2006.08.015).

 政治家们有必要区分相关的讨论中哪些是媒体舆论，哪些是公众意见。我和英国雷丁大学工作者达米安·波尔特(Damian Poulter)一起研究了英国政府发布的英国犯罪调查，试图找出什么样的人最为社区居民所顾忌。通过一系列的对比我们发现，和种族抨击、毒品、威胁和门旁噪音等不符合社会行为规范的行为相比，超速驾驶是最为人们所顾忌的。

So the challenge for governments who wish to change limits is complex. This is particularly so for those wishing to raise them, which is a less familiar path. What is clear, given the historical evidence and our biology, is that if they choose to permit faster driving, they must accept their part in the increased casualties that will follow.

 由此，政府若想调整时限将会困难重重，对于那些不按常理出牌，想要提高时限的政府来说，更是难上加难。根据历史经验和我们的生理特征，如果政府要允许一个更高的时速，那么他们也得要接受随之而上升的伤亡率。

Frank McKenna is a psychologist at the University of Reading, UK, and director of Perception and Performance, which provides consultancy on road safety to companies and government departments

弗兰克·迈金纳是英国Reading大学的心理学家，是感知与行为项目（Perception and Performance) 的主导人，这个项目主要为公司和政府部门提供有关公路安全方面的意见。