Could self-driving cars make crossings or traffic lights redundant?

Decisions made by engineers today will determine how all cars drive. Image: Grendelkhan/Flickr/creative commons.

A lot of discussion and ethical thought about self-driving cars have focused on tragic dilemmas, like hypotheticals in which a car has to decide whether to run over a group of schoolchildren or plunge off a cliff, killing its own occupants. But those sorts of situations are extreme cases.

As the most recent crash – in which a self-driving car killed a pedestrian in Tempe, Arizona – demonstrates, the mundane, everyday situations at every crosswalk, turn and intersection present much harder and broader ethical quandaries.

Ethics of extremes

As a philosopher working with engineers in Stanford’s Center for Automotive Research, I was initially surprised that we spent our lab meetings discussing what I thought was an easy question: How should a self-driving car approach a crosswalk?

My assumption had been that we would think about how a car should decide between the lives of its passengers and the lives of pedestrians. I knew how to think about such dilemmas because these crash scenarios resemble a famous philosophical brainteaser called the “trolley problem”. Imagine a runaway trolley is hurling down the tracks and is bound to hit either a group of five or a single person – would you kill one to save five?

However, many philosophers nowadays doubt that investigating such questions is a fruitful avenue of research. Barbara Fried, a colleague at Stanford, for example, has argued that tragic dilemmas make people believe ethical quandaries mostly arise in extreme and dire circumstances.

In fact, ethical quandaries are ubiquitous. Everyday, mundane situations are surprisingly messy and complex, often in subtle ways. For example: Should your city spend money on a diabetes prevention program or on more social workers? Should your local Department of Public Health hire another inspector for restaurant hygiene standards, or continue a program providing free needles and injection supplies?

These questions are extremely difficult to answer because of uncertainties about the consequences – such as who will be affected and to what degree. The solutions philosophers have proposed for extreme and desperate situations are of little help here.

The problem is similar with self-driving cars. Thinking through extreme situations and crash scenarios cannot help answer questions that arise in mundane situations.

A challenge at crosswalks

One could ask, what can be so hard about mundane traffic situations like approaching a crosswalk, driving through an intersection, or making a left turn? Even if visibility at the crosswalk is limited and it is sometimes hard to tell whether a nearby pedestrian actually wants to cross the street, drivers cope with this every day.

But for self-driving cars, such mundane situations pose a challenge in two ways.

First, there is the fact that what is easy for humans is often hard for machines. Whether it is recognising faces or riding bicycles, we are good at perception and mechanical tasks because evolution built these skills for us. That, however, makes these skills hard to teach or engineer. This is known as “Moravec’s Paradox.”

Second, in a future where all cars are self-driving cars, small changes to driving behavior would make a big difference in the aggregate. Decisions made by engineers today, in other words, will determine not how one car drives but how all cars drive. Algorithms become policy.

Engineers teach computers how to recognise faces and objects using methods of machine learning. They can use machine learning also to help self-driving cars imitate how humans drive. But this isn’t a solution: It doesn’t solve the problem that wide-ranging decisions about safety and mobility are made by engineers.

Furthermore, self-driving cars shouldn’t drive like people. Humans aren’t actually very good drivers. And they drive in ethically troubling ways, deciding whether to yield at crosswalks, based on pedestrians’ age, race and income. For example, researchers in Portland have found that black pedestrians are passed by twice as many cars and had to wait a third longer than white pedestrians before they can cross.

Self-driving cars should drive more safely, and more fairly than people do.


Mundane ethics

The ethical problems deepen when you attend to the conflicts of interest that surface in mundane situations such as crosswalks, turns and intersections.

For example, the design of self-driving cars needs to balance the safety of others – pedestrians or cyclists – with the interests of cars’ passengers. As soon as a car goes faster than walking pace, it is unable to prevent from crashing into a child that might run onto the road in the last second. But walking pace is, of course, way too slow. Everyone needs to get to places. So how should engineers strike the balance between safety and mobility? And what speed is safe enough?

There are other ethical questions that come up as well. Engineers need to make trade-offs between mobility and environmental impacts. When they’re applied across all the cars in the country, small changes in computer-controlled acceleration, cornering and braking can have huge effects on energy use and pollution emissions. How should engineers trade off travel efficiency with environmental impact?

What should the future of traffic be?

Mundane situations pose novel engineering and ethical problems, but they also lead people to question basic assumptions of the traffic system.

For myself, I began to question whether we need places called “crosswalks” at all? After all, self-driving cars can potentially make it safe to cross a road anywhere.

And it is not only crosswalks that become unnecessary. Traffic lights at intersections could be a thing of the past as well. Humans need traffic lights to make sure everyone gets to cross the intersection without crash and chaos. But self-driving cars could coordinate among themselves smoothly.

Traffic control for the future.

The bigger question here is this: given that self-driving cars are better than human drivers, why should the cars be subject to rules that were designed for human fallibility and human errors? And to extend this thought experiment, consider also the more general question: if we, as a society, could design our traffic system from scratch, what would we want it to look like?

Because these hard questions concern everyone in a city or in a society, they require a city or society to agree on answers. That means balancing competing interests in a way that works for everybody – whether people think only about crosswalks or about the traffic system as a whole.

With self-driving cars, societies can redesign their traffic systems. From the crosswalk to overall traffic design – it is mundane situations that raise really hard questions. Extreme situations are a distraction.

The ConversationThe trolley problem does not answer these hard questions.

Johannes Himmelreich, Interdisciplinary Ethics Fellow, Stanford University McCoy Family Center for Ethics in Society.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Green roofs improve cities – so why don’t all buildings have them?

The green roof at the Kennedy Centre, Washington DC. Image: Getty.

Rooftops covered with grass, vegetable gardens and lush foliage are now a common sight in many cities around the world. More and more private companies and city authorities are investing in green roofs, drawn to their wide-ranging benefits which include savings on energy costs, mitigating the risk from floods, creating habitats for urban wildlife, tackling air pollution and urban heat and even producing food.

A recent report in the UK suggested that the green roof market there is expanding at a rate of 17 per cent each year. The world’s largest rooftop farm will open in Paris in 2020, superseding similar schemes in New York City and Chicago. Stuttgart, in Germany, is thought of as “the green roof capital of Europe”, while Singapore is even installing green roofs on buses.

These increasingly radical urban designs can help cities adapt to the monumental challenges they face, such as access to resources and a lack of green space due to development. But buy-in from city authorities, businesses and other institutions is crucial to ensuring their success – as is research investigating different options to suit the variety of rooftop spaces found in cities.

A growing trend

The UK is relatively new to developing green roofs, and governments and institutions are playing a major role in spreading the practice. London is home to much of the UK’s green roof market, mainly due to forward-thinking policies such as the 2008 London Plan, which paved the way to more than double the area of green roofs in the capital.

Although London has led the way, there are now “living labs” at the Universities of Sheffield and Salford which are helping to establish the precedent elsewhere. The IGNITION project – led by the Greater Manchester Combined Authority – involves the development of a living lab at the University of Salford, with the aim of uncovering ways to convince developers and investors to adopt green roofs.

Ongoing research is showcasing how green roofs can integrate with living walls and sustainable drainage systems on the ground, such as street trees, to better manage water and make the built environment more sustainable.

Research is also demonstrating the social value of green roofs. Doctors are increasingly prescribing time spent gardening outdoors for patients dealiong with anxiety and depression. And research has found that access to even the most basic green spaces can provide a better quality of life for dementia sufferers and help prevent obesity.

An edible roof at Fenway Park, stadium of the Boston Red Sox. Image: Michael Hardman/author provided.

In North America, green roofs have become mainstream, with a wide array of expansive, accessible and food-producing roofs installed in buildings. Again, city leaders and authorities have helped push the movement forward – only recently, San Francisco created a policy requiring new buildings to have green roofs. Toronto has policies dating from the 1990s, encouraging the development of urban farms on rooftops.

These countries also benefit from having newer buildings, which make it easier to install green roofs. Being able to store and distribute water right across the rooftop is crucial to maintaining the plants on any green roof – especially on “edible roofs” which farm fruit and vegetables. And it’s much easier to create this capacity in newer buildings, which can typically hold greater weight, than retro-fit old ones. Having a stronger roof also makes it easier to grow a greater variety of plants, since the soil can be deeper.


The new normal?

For green roofs to become the norm for new developments, there needs to be buy-in from public authorities and private actors. Those responsible for maintaining buildings may have to acquire new skills, such as landscaping, and in some cases volunteers may be needed to help out. Other considerations include installing drainage paths, meeting health and safety requirements and perhaps allowing access for the public, as well as planning restrictions and disruption from regular ativities in and around the buildings during installation.

To convince investors and developers that installing green roofs is worthwhile, economic arguments are still the most important. The term “natural capital” has been developed to explain the economic value of nature; for example, measuring the money saved by installing natural solutions to protect against flood damage, adapt to climate change or help people lead healthier and happier lives.

As the expertise about green roofs grows, official standards have been developed to ensure that they are designed, built and maintained properly, and function well. Improvements in the science and technology underpinning green roof development have also led to new variations on the concept.

For example, “blue roofs” increase the capacity of buildings to hold water over longer periods of time, rather than drain away quickly – crucial in times of heavier rainfall. There are also combinations of green roofs with solar panels, and “brown roofs” which are wilder in nature and maximise biodiversity.

If the trend continues, it could create new jobs and a more vibrant and sustainable local food economy – alongside many other benefits. There are still barriers to overcome, but the evidence so far indicates that green roofs have the potential to transform cities and help them function sustainably long into the future. The success stories need to be studied and replicated elsewhere, to make green, blue, brown and food-producing roofs the norm in cities around the world.

Michael Hardman, Senior Lecturer in Urban Geography, University of Salford and Nick Davies, Research Fellow, University of Salford.

This article is republished from The Conversation under a Creative Commons license. Read the original article.