By Lance Sharpe.

We do not need to consult philosophers to find out the answer. All we need is a standard Economics textbook and pervasive technological surveillance, including (of course) facial recognition. This combination would enable the car to calculate, instantaneously to all intents and purposes, the relative net benefit to the economy of each individual under consideration in that instance, projected over their lifetime. Using a form of discounted flow analysis (DCF), each person's lifetime net value can be expressed as a value in present-day prices.

As a simple example, suppose the lifespan of average person is assumed to be 80 years. The child of, say, 5 years old who has suddenly run into the road will live another 75 years, of which around 40 will be productive. The pedestrian waiting to cross the road who is, say, 70 years old, has only 15 years to go, none of which will be productive (unless they happen to be a professor or similar). The decision for the car is clear-cut: avoid killing the child.

A more nuanced approach would be to take lifestyle factors into account as well as ago. Let's suppose the person in the car's path is a teenager, and the person waiting to cross the road is too. However, the computer network of which the facial recognition is a component recognises that teen A is a keen student who volunteers in a homeless shelter every weekend, while teen B spends his time smoking and engaging in dangerous and illegal spirits. The life expectancy of teen B is consequently less than that of teen A. Once again, the car's choice is clear.

While this sort of calculation may appear harsh, it will have a beneficial effect on both individuals and society. People, being rational, will choose the least risky options for themselves. Knowing that in a life or death situation their lifestyle may cause a driverless car to kill them, people will do all they can to improve their life chances in such a situation. Society will gain by having to devote fewer resources to dealing with smoking-related diseases, lower productivity, and the emergency services.

Yet again Adam Smith's declaration in 1776 that when individuals act in their own self-interest the whole society benefits is proven to be correct.

Tomorrow: an alternative analysis.