Climate protection through robotic taxis

Driverless vehicle fleets can dramatically reduce emissions of greenhouse gases

Driverless taxis are an extremely climate-friendly means of transport. © nature video
Read out

Taxis on autopilot: Greenhouse gas emissions in public transport could decrease by more than 90 percent if automatic vehicles are widely used by 2030. A driverless taxi fleet of interconnected electric cars would be many times more energy efficient than today's cars, US researchers have calculated. How such drastic progress affects our society, however, is difficult to estimate, the researchers say in the magazine "Nature Climate Change".

Driverless taxis are an extremely climate-friendly means of transport © nature video

Cars without drivers are anything but pure dreams of the future: Various manufacturers have already developed concepts and built prototypes. The Google Group is also testing an automatic vehicle on the road. The advantages of such cars on autopilot are obvious: Inattention or wrong decisions of the driver are based on about 90 percent of all traffic accidents. Automated and above all interconnected and coordinated vehicles would be much safer.

Up to 94 percent less greenhouse gases

A nationwide use of driverless cars would not only increase safety. Jeffery Greenblatt and Samveg Saxena of the Lawrence Berkeley National Laboratory have analyzed how much energy and greenhouse gases could be saved. In doing so, the researchers concentrated on a field of transportation that is often neglected in traffic planning in public places or lumped together with private vehicles: taxis.

The scientists created a model of the cost and greenhouse gas emissions of automatic taxis for the year 2030. The comparison of the model with emission figures from 2014 showed enormous progress: A driverless taxi in the year 2030 reduces the emission of greenhouse gases by 87 compared to a modern standard car up to 94 percent. How does this enormous savings come about?

Automated taxi fleet for every need

The biggest contributor, almost half of the savings, comes from efficient use: a single traveler gets by with a much smaller taxi than a group of four with their luggage. The researchers are counting on a whole fleet of automatic vehicles of all sizes for the future. Taxi sizes can be ordered as needed. "That saves two ways, " says Greenwald. "Smaller vehicles mean less energy consumption and lower greenhouse gas emissions." The effect is compounded when two individuals get together and book a double taxi instead of two. display

Taxis also have a major advantage over private cars: while a private user often just drives his car to and from work and otherwise stands around, Taxis are often used throughout the day. They drive so much more miles per year, so the cost-benefit calculation fills in their favor.

Small contributions pay off

This becomes particularly clear when you look at the fuel costs. Greenblatt and Saxena assume that electric cars will have prevailed widely by 2030. In addition, they expect a further increase in renewable energies such as wind power and solar energy. Electricity in its model is therefore the most favorable and climate-friendly driving force for the automatic taxi fleet. "It does not often happen that the cheapest is the 'greenest', " says Greenwald.

Since the automatic taxis will be networked together, they have another advantage: they can work together. If several such cars in a coordinated column in the slipstream, as cyclists in a long-distance race, they can save more energy. Air resistance drops and the vehicles can start and brake in harmony with each other. "These are all small contributions, " says Greenblatt, "but together they will pay off."

Uncertainty factor human

However, a major factor of uncertainty remains in the model: man. Road traffic, which in fact consists only of a fleet of automatic taxis, is still difficult to imagine today and would certainly have major social repercussions. It is difficult to say how much such a scenario would be accepted by the population. There are plenty of incentives: even without extensive vehicle fleets, the shared use of a driverless car can save a lot of money. You also gain a lot of time while not sitting behind the wheel yourself.

However, many people may be afraid to confide in traffic to a computer-controlled machine. Others could continue to use their personal vehicle as a status symbol or simply for convenience. In addition, individuals could order a larger cab than they actually need to have more space this, too, would lower the model's energy efficiency. And last but not least, it is completely unclear to what extent politics and bourgeoisie can or want to enable a comprehensive system of automatic taxis. (Nature Climate Change, 2014; doi: 10.1038 / nclimate2685)

(DOE / Lawrence Berkeley National Laboratory, 07.07.2015 - AKR)