Why drivers of vans UPS in America never turn left?

it May seem strange, but the vans of the American company UPS do not always choose the shortest route between stops. The company provides each driver a specific route which he should follow, and it is designed according to the notion that drivers should not turn across oncoming traffic unless it is absolutely necessary. This means that the routes are sometimes much longer than they should be. So, why do they do it?

routing

Every day, along with other companies, UPS solves the routing problem of vehicles. In these tasks, they get a lot of points and the distances between them, and must find the best route to travel through them. Overall, the best is the route with the shortest distance.

the routing Problem of vehicles are used for a huge number of things, including for dealing with a large number of vans in the cities. This notion was introduced by George Danzig in 1959. Even 50 years later, despite the large amount of research, scientists are looking for new ways to solve this problem.

company Policy UPS

UPS has moved away from attempts to find the shortest route, and is now considering other criteria to optimize the path. One of these methods – an attempt to avoid turning into oncoming traffic at intersections. Despite the fact that the path can go in the opposite direction from the final destination, such a policy reduces the chances of delays due to accidents and waiting time in traffic jams, which also saves fuel.

UPS has developed its own software routing of vehicles to eliminate as many left turns as possible (in countries with right-hand traffic).

Economy

As a rule, during the trip the driver makes a left turn in 10% of cases. The company claims that as a result they save about 40 million liters of fuel, emit 20,000 tonnes less of carbon dioxide, while delivering more than 350,000 parcels each year. Efficient route planning with a navigation software even helped the firm to abandon the 1,100 trucks that it uses, bringing the total distance decreased by 45 million kilometers, despite the longer routes.

Seems incredible that the rejection of left turns can lead to such significant savings. This idea was even tested in the television show “Mythbusters”, which confirmed that, despite the longer distance, only right turns saves fuel. In their experiment on the same truck they drove on, but when transferring this result to the global level, it became clear that the UPS vans do passing less kilometers in total.
In connection with the success of the policy of UPS, the question arises, why don't we all refuse to turn to the left (or right, depending on which country you live) when tooling around town. If all start doing it, the reduction of carbon emissions into the atmosphere will be huge and will probably decrease the amount of congestion.


the Problem is that not every trip will be more effective if you follow this strategy, and most people will likely change their driving style just in case if they have personal benefit.

the Dilemma of the driver

As in everything connected with the struggle against climate change if everyone else did it the situation would change for the better, and you wouldn't have to change your way of life in favor of others. But if only a few people will not want to follow this rule, the whole system will fail.
This is a good example of the prisoner's dilemma – famous problems of the theory of games. If all cooperate, the system overall will be much better. But the most benefit will get people who will refuse to interact with others and will reap the fruits of labor those who made sacrifices.

of Course, you can't convince people to always turn right for the good of each person, but the initiative must come from the government, which may encourage drivers or even apply a certain strategy. For example, we would plan the roads that make the left turn through lane. To accomplish this, you need a bold planner, but if UPS can save 40 million litres of fuel, how many will be able to save a whole city or country?