Here's why UPS drivers don’t turn left – and you probably shouldn’t either

Turn right, Donna Noble, and change the world. Image: Getty.

It might seem strange, but UPS delivery vans don’t always take the shortest route between stops. The company gives each driver a specific route to follow and that includes a policy that drivers should never turn through oncoming traffic (that’s left in countries where they drive on the right and vice versa) unless absolutely necessary. This means that routes are sometimes longer than they have to be. So, why do they do it?

Every day, along with thousands of other companies, UPS solves versions of the vehicle routing problem. In these mathematical problems, you are given a set of points and the distances between them, and you have to find the best route(s) to travel through all of them. Best is usually defined as the route with the shortest overall distance.

Vehicle routing problems are used to organise many things, from coping with more delivery trucks in cities and hailing taxis to catching chickens on a farm. The concept was introduced by George Dantzig in 1959. Over 50 years later, and despite a large body of scientific research, scientists are still looking for new ways to tackle the problem.

Vehicle routing problems involve finding the best route between points. Image: Wikipedia Commons.

UPS have moved away from trying to find the shortest route and now look at other criteria to optimise the journey. One of their methods is to try and avoid turning through oncoming traffic at a junction. Although this might be going in the opposite direction of the final destination, it reduces the chances of an accident and cuts delays caused by waiting for a gap in the traffic, which would also waste fuel.

UPS have designed their vehicle routing software to eliminate as many left-hand turns as possible (in countries with right-hand traffic). Typically, only 10 per cent of the turns are left turns. As a result, the company claims it uses 10m gallons less fuel, emits 20,000 tonnes less carbon dioxide and delivers 350,000 more packages every year. The efficiency of planning routes with its navigation software this way has even helped the firm cut the number of trucks it uses by 1,100, bringing down the company’s total distance travelled by 28.5m miles – despite the longer routes.

It seems incredible that not turning left can lead to such significant savings. The TV series Mythbusters tested this idea and confirmed that, despite many more turns, the policy of only turning right does save fuel. In their one truck experiment they travelled further, but when you scale this up to a global level, UPS really does travel fewer miles in total.

The success of UPS’s policy raises the question, why don’t we all avoid turning left (or right, depending on what country we’re in), as we drive around cities on our daily commutes? If everyone did it, the carbon savings would be huge and there’d probably be far less congestion.

The problem is that not every journey would be made more efficient by following this strategy, and most people are likely only to change their driving style if they personally benefit.


Driver’s dilemma

As with anything related to reducing climate change, if everybody else did it then things would get better and you wouldn’t have to change your lifestyle at all to benefit. But it only needs a few people to not cooperate and the whole system breaks down.

This is a good example of the prisoner’s dilemma, the famous game theory problem. If everybody cooperated then the system as a whole would be much better, but the best thing for an individual when everyone else is cooperating is to be uncooperative and reap the rewards of everybody else’s sacrifices.

So, if you cannot persuade people to always turn right (or left) for the benefit of everyone, it might be down to governments to encourage or even enforce the strategy. For example, we could plan roads that make it more difficult to turn through the traffic. It would take a brave city planner to implement this, but if UPS can save 10m gallons of fuel, how much could a whole city or even a whole country save?The Conversation

Graham Kendall is professor of computer science and At the University of Nottingham.

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

 
 
 
 

Here’s how we plant 2 billion more trees in the UK

A tree in Northallerton, North Yorkshire. Image: Getty.

The UK’s official climate advisor, the Committee on Climate Change (CCC), recently published a report outlining how to reduce the 12 per cent of greenhouse gas emissions that come from land use by two thirds by 2050. Alongside recommending cutting meat and dairy consumption by 20 per cent, the report calls for the annual creation of up to 50,000 hectares of broadleaf and conifer woodland for the next three decades. This would increase forest cover from 13 per cent to at least 17 per cent – a level not seen in Britain since before the Norman invasion.

Reforestation at that rate would mean creating roughly the area of the city of Leeds every year for the next three decades. At typical stocking densities of 1,500 stems per hectare, the ambition is to establish some 2.25 billion additional trees. Given that the UK, as with most of Europe, is in the grip of ash dieback, a disease likely to prove fatal for many millions of native ash trees, the scale of the challenge is massive.

On a crowded and intensively farmed island like Britain, unlocking a million and a half hectares of land will be no mean feat. But it’s not impossible – and is an unprecedented opportunity not only to tackle the climate crisis but also the biodiversity crisis that is every bit as detrimental to our wellbeing.

Trees and farms

One million and a half hectares is just 6 per cent of the mainland UK’s land area. To give some sense of perspective on this, 696,000 hectares of “temporary grassland” were registered in 2019. So if land supply is not the problem, what is? Often it’s cultural inertia. Farmers are firmly rooted to the land and perhaps understandably reluctant to stop producing food and instead become foresters. But the choice need not be so binary.

The intensification of agriculture has caused catastrophic declines in many species throughout the UK by reducing vast wooded areas and thousands of miles of hedgerows to small pockets of vegetation, isolating populations and making them more vulnerable to extinction.

Integrating trees with the farmed landscape delivers multiple benefits for farms and the environment. Reforestation doesn’t have to mean a return to the ecologically and culturally inappropriate single-species blocks of non-native conifers, which were planted en masse in the 1970s and 1980s. Incentivised under tax breaks to secure a domestic timber supply, many of the resulting plantations were located in places difficult or in some cases impossible to actually harvest.

Productive farmland needn’t be converted to woodland. Instead, that 4 per cent of land could be found by scattering trees more widely. After all, more trees on farmland is good for business. They prevent soil erosion and the run-off of pollutants, provide shade and shelter for livestock, a useful source of renewable fuel and year-round forage for pollinating insects.

The first tranche of tree planting could involve new hedgerows full of large trees, preferably with wide headlands of permanently untilled soils, providing further wildlife refuge.


Natural regeneration

Where appropriate, new woody habitats can be created simply by stopping how the land is currently used, such as by removing livestock. This process can be helped by scattering seeds in areas where seed sources are low. But patience is a virtue. If people can learn to tolerate less clipped and manicured landscapes, nature can run its own course.

A focus on deliberate tree planting also raises uncomfortable truths. Most trees are planted with an accompanying stake to keep them upright and a plastic shelter that protects the sapling from grazing damage. All too often, these shelters aren’t retrieved. Left to the elements, they break down into ever smaller pieces, and can be swept into rivers and eventually the ocean, where they threaten marine wildlife. Two billion tree shelters is a lot of plastic.

The main reason for using tree shelters at all is because the deer population in the UK is so high that in many places, it is all but impossible to establish new trees. This also has serious implications for existing woodland, which is prevented from naturally regenerating. In time, these trees will age and die, threatening the loss of the woodland itself. Climate change, pests and pathogens and the lack of a coordinated, centrally supported approach to deer management means the outlook for the UK’s existing treescape is uncertain at best.

An ecologically joined-up solution would be to reintroduce the natural predators of deer, such as lynx, wolves, and bears. Whether rewilding should get that far in the UK is still the subject of debate. Before that, perhaps the focus should be on providing the necessary habitat, rich in native trees.

A positive response would be to implement the balanced recommendations, made almost a decade ago in a government review, of creating more new habitat, improving what’s already there, and finding ways to link it together. Bigger, better, and more connected habitats.

But the UK is losing trees at increasing rates and not just through diseases. The recent removal of Victorian-era street trees in Sheffield and many other towns and cities is another issue to contend with. As the climate warms, increasing urban temperatures will mean cities need shade from street trees more than ever.

Trees aren’t the environmental panacea that the politicians might have people believe – even if they do make for great photo opportunities – but we do need more of them. Efforts to expand tree cover are underway across the world and the UK will benefit from contributing its share. Hitting the right balance – some commercial forestry, lots of new native woodland and millions of scattered trees – will be key to maximising the benefits they bring.

Nick Atkinson, Senior Lecturer in Ecology & Conservation, Nottingham Trent University.

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