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Autonomously driven trucks can salve the toll of drivers. Assembling into platoons (what used to be called convoys) that depart at regular intervals raises scheduling efficiency. Truck platoons that are closely bunched for aerodynamic efficiency can relieve upwards to 20% on fuel costs. This is all according to new research from Massachusetts Plant of Engineering science.

The more trucks in the convoy, the meliorate the efficiency — considering the first and last don't garner the full furnishings of drafting. MIT found it'south most efficient to have a flock of trucks get out the marshaling k at fixed times, or acceleration once a minimum number of trucks have shown up. The research is virtually mathematical models, not near how civilian drivers on the interstate similar the idea of a wall of trucks in the right lane.

Source: Freightliner

Source: Freightliner

Larn from flocks of birds, or drafting bike racers

Traveling in close proximity boosts fuel efficiency. "Ride-sharing and truck platooning, and even flocking birds and [fighter jet] formation flight, are like issues from a systems point of view," says MIT professor Sertac Karaman, likewise with bicyclists or race drivers drafting in a pack. He adds, "People who study these systems simply wait at efficiency metrics like delay and throughput. Nosotros look at those aforementioned metrics, versus sustainability such every bit cost, free energy, and environmental impact. This line of inquiry might really turn transportation on its head."

MIT was as well concerned with the costs of vehicles waiting effectually before heading out, and similarly the cost and annoyance of passengers in ride sharing services or passenger buses waiting to depart. In a session this week in San Francisco at the International Workshop on the Algorithmic Foundations of Robotics, Karaman and colleagues compared regular interval departures with a feedback policy, where vehicles gather and and so depart only in one case a minimum number of vehicles are gathered.

World Premiere Freightliner Inspiration Truck

Simple policies work best

What the MIT research team found was this: "The simplest policies incurred the to the lowest degree delays while saving the well-nigh fuel." That is, deploying platoons of trucks at stock-still divergence times was more sustainable and efficient than staggered interval departures. At the same time, waiting for the same number of trucks to convoy was more than efficient than varying the size of the convoy.

Between the two, fixed departure fourth dimension versus feedback scenarios, the feedback policies saved about five% more than in fuel. "You'd think a more complicated scheme would save more energy and fourth dimension," Karaman said. "Just … in the long run, it's the simpler policies that help y'all."

Truck convoy mpg

Pack the trucks closely for aerodynamic efficiency

Karaman is working with trucking companies in Brazil to set upwards models for efficiency transportation. The not-however-final model suggests trucks follow closely at 3-4 meters (10-13 feet) to maximize aerodynamic savings. Since the model for homo driven cars is 3 seconds betwixt vehicles, or 264 anxiety at 60 mph, and even the most skilled human tin can't maintain a 10-human foot gap for sustained periods, this means the vehicles volition be autonomous.

According to MIT, previous research shows: "Scientists have previously calculated that if several trucks were to drive merely a few meters apart, one behind the other, those in the center should experience less drag, saving fuel by as much as 20%, while the concluding truck should save xv% — or slightly less, due to air currents that drag behind. Assuming this and the lead truck gaining 10%, a five-truck convoy would save 17% on fuel compared to unmarried trucks, eight would come across an 18% proceeds, and only at fifteen trucks would efficiency reach 19%." In other words, in that location's a diminishing return afterwards convoys of well-nigh x trucks.

Not studied: How others on the highway see convoys

Studies can't written report everything. Here, in that location's nothing most the reaction of other motorists who aren't part of the convoy. It'due south likely some — a lot, maybe — other drivers will accept qualms initially about sharing the road with self-driving vehicles. Forget for a moment that the safer vehicles on the route may be the ones driven autonomously. They'll have routines for self-driving, and too for how to get off the road safely if in that location'south a malfunction or flat tire. It may exist that self-driving trucks would starting time with a driver in each truck (who sits back once it's on the interstate), shifting over time to a atomic number 82 driver only, and and so doing away with the lead driver entirely.

If the trucks are loosely spaced, so there'southward room for homo-driven cars to ride betwixt the trucks if desired, that's one thing. Merely to have a solid wall of trucks stretching for several hundred yards might exist even more than disconcerting. (A x-truck convoy with a fuel-saving spacing of 10 feet would stretch about 750 feet, 0r 0.xv miles.) MIT'south enquiry examples talked about a handful of trucks in a platoon.