Study that traffic congestion decreases by mere mixing of several automatic driving cars on the road

By gscruton

A research result was announced that the automatic driving car which development advanced mainly in the United States and China, in addition to enabling safe driving, may be able to reduce road congestion by utilizing machine learning.

Watch just a few self-driving cars stop traffic jams | Science | AAAS
https://www.sciencemag.org/news/2018/11/watch-just-few-self-driving-cars-stop-traffic-jams

While driving a car, I often encounter traffic jams, but there are traffic jams caused by accidents and constructions, but I do not know the cause at all and "The congestion is over but I do not know what the traffic jam Many people have ever encountered a strange traffic jam that you thought?!? According to traffic engineering research, the traffic jam that has been considered unknown is that one car steps on a brake that does not need an unnecessary brake to turn on the brake lamp also cars that run behind will step on the brakes, further cars behind it ... It is understood that as the brake is stepped on the wind in a chain, gradually many cars slow down the speed and finally it even produces a situation of completely stopping.

This "back shock wave" of the brake is often caused by a human driver. Research is being carried out to make artificial intelligence (AI) machine learning so as to reflect on the way the automatic driving car runs so as not to operate unnecessary brakes if it is originally necessary.

The research team leads research teams such as Eugene Vinitsky of the University of California, Berkeley (UCLA). Studies are being made to create a smooth road flow that does not cause traffic congestion by letting AI learn how to run with reinforcement learning. The team developed an algorithm "FLOW" to prevent the occurrence of traffic congestion and investigates how much traffic congestion can be prevented by running simulation combined with human drivers.

One example is the next two movies. Both simulations that 22 cars run on a circular road, driving is simulating 22 people in the first movie. Although it seems to be flowing smoothly at first, it gradually begins to approach the distance between vehicles, and finally it develops into a heavy traffic jam that will stop completely.

Single-lane ring (0 AVs, 22 human-driven vehicles) - YouTube


However, when one automatic driving car (AV) is introduced here, the situation has changed completely. The group's "fluctuation" is absorbed thanks to the automatic driving car which keeps a proper distance between people, wasteful acceleration and deceleration disappears and congestion no longer occurs like a lie.

Single-lane ring (1 AV, 21 human-driven vehicles) - YouTube


The situation seems to happen even in situations where the road intersects the eight characters. With human driving, traffic jams occur at intersections like the following movies ......

Figure 8 (0 AVs, 14 human-driven vehicles) - YouTube


When the automatic driving car enters, the whole will become smoothly flowing. It seems to be said that it is a big reason to measure the timing of the movement in the first part, but maybe you are avoiding a cold at the intersection by exquisitely adjusting the speed even after running.

Figure 8 (1 AV, 13 human-driven vehicles) - YouTube


An important point of the above movie is that "the occurrence of traffic congestion can be suppressed by making an appropriate interval". As the distance between vehicles becomes smaller, the following drivers will surely step on more brakes. Then traffic congestion will occur with the chain that the driver following the brake lamp that lighted stepped on the brake again.

The next two movies that understand the situation well. It is a situation simulating a road that joins the main road of the expressway, but when the cars join from the branch line where the car is flowing all the time on the main line, traffic jams occurred as a result, and the stagnation continues steadily It will become.

Merge 0% CAV Penetration - YouTube


On the other hand, if there is a moderate "buffer" in the flow of the main line, you can see that even if a traffic jam occurs, the buffer will absorb fluctuations and prevent congestion from becoming chain-like longer . If you look closely, you can also see that the following automatic driving cars change the way you drive by recognizing the situation in front of you.

Merge 5% CAV Penetration - YouTube


In this way, in order to suppress the occurrence of traffic congestion it is important to have a moderate buffer in the flow, and the research result shows that the automatic driving car seems to be useful for realizing that. Nonetheless, that buffer is not necessarily just made by AI, but human drivers can only reproduce with a little thought. Like the word "hurrying up", traffic congestion may be avoided just by a lot of people trying to drive with relaxation.

On the other hand, it seems to be important to understand that there is also the idea that "congestion deteriorates due to automatic driving cars."

Traffic congestion dramatically worsens as the automated driving car runs - GIGAZINE

The research team has released the traffic jam avoidance algorithm "Flow", so if you are interested, try getting it from the link below.

Flow
https://flow-project.github.io/index.html