What is the Relationship Between Connected and Automated Vehicles?

If you follow news about connected and automated vehicles, you’ve no doubt seen the terms “connected” and “automated” used frequently, and at times, almost interchangeably.

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In fact, connectivity and automation are two entirely different technologies, although they share many objectives in terms of improving safety and mobility. Many in the industry believe that the combined use of the two technologies is necessary to achieve the most positive outcomes.

Connected vehicle (CV) refers to the digital exchange of data between vehicles (vehicle to vehicle or V2V), other transportation users (vehicle to anything, or V2X), and the roadside (vehicle to infrastructure, or V2I), using wireless communications.

CVs will continuously broadcast information (including location, speed, acceleration, heading and other parameters) to nearby vehicles that can use the information to identify a potential collision, for example. The radio technology used can detect a nearby vehicle maneuver that may be a threat outside of the immediate field of view for the driver—such as two vehicles ahead suddenly stopping—and alert the driver of the threat.

As the name implies, automated driving systems automate some or all the driving tasks performed by humans. To understand and respond to their surroundings, including infrastructure and other roadway users, automated vehicles (AV) generally rely on a suite of sensors, such as radar, light detection and ranging (LiDAR) and vision systems, as well as high-resolution digital mapping.

While AVs are most commonly thought of as fully self-driving vehicles that can execute all driving tasks independently, there is a wide range of automated features, many of which are available todaysuch as parallel parking assist, emergency braking functions, and adaptive cruise controlwhich provides limited automated driving functions on highways.

The Society of Automotive Engineers has defined levels of automation on a 0-5 system, with Level 5 representing full automation under all driving conditions. Today, vehicles with Level 1 and even some Level 2 functionality are commercially available.

Working Together

So how are connected and automated vehicles related? Let’s take a look at a traffic signal as an example.

An AV without connectivity is simply using on-board sensors to determine its surroundings. As the AV approaches a traffic signal, much like a human driver, the AV must rely on “seeing” the traffic signal with its sensors and determine from that input whether the signal is red, yellow or green, and how to respond. The AV therefore has no context beyond what a human driver would have. If a large truck is positioned in front of the AV, or if there is heavy rain or snowfall, the AV may be similarly impaired in terms of seeing the traffic signal and determining a response.

However, if the AV were also a connected vehicle, it could receive continuous radio messages from the traffic signal, indicating not only the current signal indication (red/yellow/green), but also the time until the next phase change, providing additional context for determining the speed for approaching the intersection.

In a fully connected system, that information could also help to inform the vehicle of the optimum travel speed to avoid stopping at the next intersection. And while the on-board sensors may not have clear visibility of another vehicle on the nearby cross-street, V2V communication could inform the AV of a vehicle about to violate the red light, allowing it to avoid a potential collision that it might not otherwise be able to detect with sensors alone.

While connected and automated vehicles are two very different things, together these two technologies can make our roadways much safer in the years to come.

Scott Shogan, connected/automated vehicle market leader with WSP USA, has two decades of traffic engineering and intelligent transportation systems experience. His expertise includes traffic operations analysis, microsimulation, and the planning and design of technology applications for improving traffic operations and safety.

[Editor’s Note: To learn more about how WSP supports the planning, deployment and maintenance of intelligent transportation systems and connected and automated vehicle projects across the U.S., visit www.advancingtransport.com.]

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