Are Autonomous Vehicles the Answer to Safer, Smoother Traffic?
Connected autonomous vehicles could communicate with each other to ease traffic. (Image: U.S. Department of Transportation)
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[Cars honking, traffic sounds]
Esther Oyedele: Imagine rush hour without frustration. No honking, no gridlock, just cars gliding smoothly down the road. This could be the future with autonomous vehicles, or AVs. But as Ali Hajbabaie, an associate professor at North Carolina State University explained, the journey to this vision isn’t as simple as it seems.
During the New Horizons in Science briefing at the ScienceWriters2024 conference in Raleigh, N.C., Hajbabaie shared how AVs could change traffic—potentially for the better or worse.
Ali Hajbabaie: Everyone thinks that if the flow is a 100% AV, things are going to get better now. It’s not going to get better now. The technology is not there. It’s going to get worse.
Oyedele: His research looks at how traffic behaves when human-driven cars and AVs share the road. By running computer simulations, his team studies how cars interact, from small intersections to big highway systems.
Autonomous vehicles or AVs are self-driving cars equipped with sensors that let them do some or all of the driving tasks.
But not all AVs are created equal. There’s a spectrum of autonomy, ranging from level 0, where drivers are full control, to level 5 where the car is entirely self-driving—no steering wheel, gas pedal, or even a driver’s seat. Most of today’s AVs are at level 4 autonomy. This means they can operate independently but only in specific areas that have been mapped out in advance.
Even then, they are not entirely on their own. Level 4 AVs still need remote supervision—for instance, an operator in a control center monitoring their performance and extra safety systems on board to handle unexpected situations.
Well, let’s just say in simpler terms, these cars are smart, but not yet smart enough to handle every situation without a little help.
For traffic to truly flow better, Hajbabaie says it’s not just about smarter cars, it’s about smarter connections.
Hajbabaie: When you have connected automated vehicles, there is a lot more that can be done that we cannot do…with only autonomous vehicles.
Oyedele: Connected autonomous vehicles, or CAVs, are vehicles that talk to each other and to traffic infrastructure like traffic lights. This constant sharing of information can help ease congestion and cut down on pollution.
One exciting concept is the white light signal. Unlike red, yellow, or green, this light activates only when enough connected vehicles are at an intersection. For AVs, it sends speed instructions wirelessly so they glide more smoothly. For humans, it’s a simple message: Just follow the car in front of you without changing the lane.
Hajbabaie’s research shows this could cut delays at intersections by up to 14.7 percent.
Hajbabaie: Connectivity is really a major player in improving traffic operations and safety in the presence of autonomous vehicles. So to me, if we want to have transportation systems that work much better than what we have, like traffic systems that work much better than what we have, we cannot only rely on autonomy. It has to be autonomy and connectivity.
Oyedele: Looking ahead, his team is expending their studies to include buses, bikes, and even pedestrians, while preparing for challenges like communication failures and unpredictable human behavior.
So, can AVs actually solve our traffic woes? Well, not on their own, but with connectivity and innovations like the white light, the future of transportation looks promising.
This has been Esther Oyedele reporting from the Council for the Advancement of Science Writing Newsroom. Thank you for listening.
