driverless car driving

Driverless cars shown to ease traffic congestion among human-driven vehicles

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The addition of a small number of autonomous vehicles (AVs) on the roads could help traffic to flow faster, safer and with fewer emissions, a study has found.

The team from Bar-Ilan University in Tel Aviv modelled the flow of hybrid traffic, that which combines traditional, human-operated vehicles with a small fraction of AVs.

They developed a simple set of guidelines and regulations that allow AVs to be self-organised into constellations. Through this, dynamic control of traffic flow is made possible.

The guidelines promote cooperation between AVs that mean that even when fewer than 5 per cent of the vehicles on the road are autonomous, they can still have an impact on the traffic flow.

The researchers describe how AVs should behave on a freeway in order to self-organise into groups that split the traffic flow into controllable clusters.

It was observed that it takes less than two minutes to achieve self-organised high-speed, greener and safer traffic flow when starting from congested traffic.

“Without regulations on AVs, we face a classic example of game theory paradox, such as the prisoner’s dilemma, where each vehicle tries to optimise its driving speed but the overall traffic flow is not optimal. In our research we examine how, with proper regulations, a very small number of AVs can improve the overall traffic flow significantly, through cooperation,” said Dr Amir Goldental.

Quantitatively, the authors report a substantial increase of up to 40 per cent in traffic flow speed with up to a 28 per cent decrease in fuel consumption.

Traffic safety is also enhanced as traffic becomes more ordered and fewer lane transitions occur.

The study shows that these improvements can be achieved without a central agent that governs AVs and without communication between AVs using current infrastructure.

However, a study in 2017 suggested that the introduction of AVs may actually increase congestion on the roads, at least temporarily, due to the “cautious” nature of the vehicles in comparison to human drivers.

It has also been demonstrated that with driverless vehicles open to hacking, just 20 per cent of traffic would need to be stalled to cause total gridlock in a city like New York. 

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