Vehicle-to-Everything (V2X): How Cars Will Talk to Traffic Lights

Sitting at a red light when no other cars are around is a universal frustration. Fortunately, the era of guessing when a light will turn green is ending. Vehicle-to-Everything technology is transforming cars into smart devices that communicate directly with city intersections to save time, fuel, and lives.

What Exactly is Vehicle-to-Everything (V2X)?

Vehicle-to-Everything is an umbrella term for a communication network that allows your car to talk to its surroundings. This technology breaks down into a few specific categories. Vehicle-to-Vehicle (V2V) lets cars talk to each other to prevent crashes. Vehicle-to-Pedestrian (V2P) detects people walking or biking. However, the most immediate impact on your daily commute comes from Vehicle-to-Infrastructure, commonly known as V2I.

V2I is the specific protocol that lets your vehicle exchange data with traffic lights, toll booths, and school zone signs. Instead of relying purely on cameras or radar to see a red light, your car receives a digital signal from the traffic light itself. This creates a hidden network of information flowing back and forth between the city streets and your dashboard.

The Hardware and Networks Behind the Magic

For years, automakers and tech companies debated how these networks should operate. Today, the auto industry has largely settled on a standard called Cellular V2X (C-V2X). This system uses the same basic 5G cellular technology that powers your smartphone.

To make this work, the Federal Communications Commission (FCC) specifically reserved a chunk of the wireless spectrum in the 5.9 GHz band strictly for transportation safety. Because it has its own dedicated lane in the radio spectrum, the data moves incredibly fast without interference from regular cell phone traffic.

Major tech companies are already building the hardware. Qualcomm makes the Snapdragon Auto 5G modems that automakers install inside new cars to process these signals. On the city side, companies like Commsignia and Panasonic manufacture Roadside Units (RSUs). These small, weather-proof boxes get mounted directly onto traffic light poles. The RSU broadcasts the current color of the light and the exact fraction of a second when it will change.

Real-World Proof: Audi's Traffic Light Information

This technology is not science fiction. You can experience it right now. Audi was the first major automaker to bring this feature to consumers, launching its Traffic Light Information (TLI) system back in 2016. The company has since expanded the feature to most of its lineup, including popular models like the Audi A4, Q5, and Q7.

Audi partners with a data management company called Traffic Technology Services. This company aggregates live data from municipal traffic control centers in cities like Las Vegas, Dallas, and Washington D.C. When you drive a newer Audi in these supported cities, you gain access to two distinct features.

First, you get a “Time-to-Green” countdown on your dashboard. If you are stopped at a red light, a timer shows exactly how many seconds remain until the light turns green. Second, Audi offers a Green Light Optimized Speed Advisory (GLOSA). As you drive toward a green light, your dashboard displays a recommended speed. If you drive exactly that speed, you will pass through the intersection without ever having to touch your brakes.

The Federal Push for Widespread Adoption

While Audi took the early lead, the United States government is now stepping in to ensure every car brand gets on board. In August 2024, the U.S. Department of Transportation (USDOT) published a comprehensive national V2X deployment plan.

The USDOT set very aggressive targets for the upcoming decade. The government wants 20 percent of the National Highway System equipped with V2X technology by 2028. Looking further ahead, the plan aims for 100 percent coverage across the national highway network by 2036. The government is also offering major grants to cities to help them afford the physical Roadside Units needed for their traffic lights.

Ford is another major player answering this call. The company has publicly committed to deploying C-V2X technology in its upcoming vehicle models, which will help push the technology from luxury vehicles into mainstream pickup trucks and SUVs.

Why Traffic Light Communication Matters

The primary reason the government and automakers are spending billions on V2X is safety. The National Highway Traffic Safety Administration (NHTSA) estimates that V2X technology could help prevent up to 80 percent of crashes involving non-impaired drivers. Intersections are incredibly dangerous spots. With V2X, your car will automatically hit the brakes if it detects that a truck hidden behind a building is about to run a red light.

Beyond safety, talking to traffic lights saves fuel and reduces emissions. Idling at red lights wastes billions of gallons of gasoline in the United States every year. By using speed advisories to catch green lights, drivers experience smoother trips. This reduces the heavy braking and hard acceleration that burns excess fuel and wears out brake pads. In a fully connected city, traffic lights can even adjust their own timing on the fly based on the exact number of connected cars approaching the intersection.

Frequently Asked Questions

Do I need to pay for a 5G subscription to use V2X? In most cases, automakers bundle the connectivity needed for basic safety features into the purchase price of the car. However, premium convenience features (like Audi’s dashboard countdown timer) often require an active subscription to the automaker’s connected services package.

Is my location tracked when my car talks to a traffic light? No. V2X systems are designed around privacy. Cars broadcast Basic Safety Messages (BSMs) up to ten times a second. These messages contain speed, direction, and location, but they do not contain your vehicle identification number, name, or license plate. The data is anonymized and constantly rotated to prevent tracking.

Can older cars be upgraded to talk to traffic lights? Currently, retrofitting an older car with integrated C-V2X dashboard technology is very difficult. However, some aftermarket companies are developing smartphone apps and dashcams that pull traffic light data from the cloud, giving older vehicles a similar experience without the built-in hardware.