You’ve seen the videos. It’s 4:00 AM in a San Francisco parking lot. There aren't any humans in sight, just a fleet of white Jaguar I-PACE SUVs slowly circling one another like some kind of high-tech interpretive dance. Then, it starts. A chirp. A blast. A full-on chorus of Waymo honking at each other while the rest of the neighborhood is trying to sleep.
It looks ridiculous. Honestly, it looks like the robots are having a disagreement or, as some local residents joked on TikTok, they’re starting a very polite mechanical uprising. But the reality of why these autonomous vehicles (AVs) are making so much noise in the dead of night says a lot about the current "brain" of self-driving tech. It isn’t a glitch in the way you’d think. It’s actually a safety feature that worked a little too well.
The San Francisco Cul-de-Sac Incident
The most famous instance of this happened in a parking lot in the SoMa neighborhood. Waymo uses these lots as "depots" or staging areas. When the cars aren't out picking up passengers, they head back to these spaces to wait or recharge.
The problem? Space is tight.
When one Waymo was backing out of a spot and another was pulling in, the software triggered a "collision avoidance" protocol. In the world of an AV, if something gets too close and doesn't seem to be moving, the car is programmed to alert the "other driver." But in this case, the other driver was just another Waymo following its own logic.
Imagine two people trying to walk through a narrow doorway at the same time. Both step to the left. Both step to the right. Both say "Ope, sorry!" Except instead of a polite midwestern apology, these cars are programmed to emit a loud, 110-decibel honk to ensure they are noticed. Because the cars were performing these maneuvers dozens of times an hour as the fleet cycled through, the neighborhood turned into a cacophony of robotic frustration.
Why Do Robots Need to Honk?
You might wonder why a car that can "see" in 360 degrees using LiDAR, radar, and cameras needs to make noise at all. If the cars are connected to the same cloud, can't they just whisper to each other over Wi-Fi?
Well, they could. But Waymo's engineers have a very specific philosophy: the car must behave in a way that humans understand.
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If a Waymo is backing up and senses an object—whether it's a trash can, a stray dog, or another Jaguar—it uses the horn as a universal signal. It's a "Look at me, I'm here!" warning. The software doesn't necessarily distinguish between "that's a human-driven Honda I need to warn" and "that's my buddy from the same fleet." It just sees a potential collision risk.
Actually, the horn logic is a bit more nuanced than a standard car alarm. Waymo uses different "honk profiles." A short tap is a friendly "hey, the light is green" or "I'm here." A longer blast is reserved for higher-stakes situations. During the parking lot fiascos, the cars were mostly using the shorter, repetitive chirps, but when you have twenty cars doing it simultaneously, it sounds like a digital aviary gone wrong.
The Software Patch That Quieted the Fleet
After the videos went viral and neighbors started showing up to city council meetings with dark circles under their eyes, Waymo had to move fast. They didn't just turn the horns off. That would be a massive safety liability. Instead, they had to teach the cars "neighborhood awareness."
They pushed an over-the-air (OTA) update specifically designed to handle these low-speed, fleet-heavy environments. The cars now recognize when they are in a designated Waymo staging area. When they’re in these "safe zones," the threshold for honking is much higher. They rely more on their sensors and internal coordination rather than external noise.
Waymo spokesperson Chris Bonelli eventually clarified that the issue stemmed from the cars' inability to recognize each other as "friendly" in close-quarters maneuvering. Basically, the cars were treating their own teammates like unpredictable strangers.
It’s Not Just San Francisco
While the SF parking lot is the most cited example, reports of Waymo honking at each other have popped up in Phoenix and Los Angeles too.
In Phoenix, the heat can sometimes mess with how sensors perceive distances, leading to "ghost" obstacles. If a car thinks there’s a hazard that isn't there, it might honk to warn the non-existent hazard. But more often, it's about the "unprotected left turn."
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We humans hate them. Robots hate them more.
When a Waymo is trying to turn left and another Waymo is coming the other way, they both play it incredibly safe. Sometimes, they get into a "deadlock" where neither wants to go first. If a third car (maybe a human) gets impatient and starts inching up, the Waymo might honk to assert its space.
The Reality of Edge Cases
This whole situation is what engineers call an "edge case."
When you’re building a self-driving car, you spend 90% of your time on the easy stuff: staying in lanes, stopping at red lights, not hitting pedestrians. The last 10% is the hard part. The weird stuff. Like what happens when two robots meet in a dark alley at 3 AM.
We’re essentially watching the awkward teenage years of artificial intelligence. The cars are incredibly smart, yet they can be tripped up by the simplest social cues. Humans use eye contact to negotiate who goes first at a four-way stop. Waymos use centimeters of movement and, occasionally, a loud horn.
What This Means for the Future of Cities
As Waymo expands to Austin and beyond, the "honking problem" serves as a reminder that the infrastructure of our cities isn't quite ready for a silent, robotic takeover. We have noise ordinances for a reason.
If we want 24/7 autonomous taxis, we have to accept that these machines will occasionally have "disagreements." However, the fact that Waymo could fix the San Francisco honking issue with a software update in just a few days is actually a huge testament to how this tech evolves. A human driver who likes to honk is a permanent nuisance. A robot that honks can be reprogrammed to be quiet by Monday morning.
Practical Steps for Living with Autonomous Fleets
If you live in a city where Waymo or other AVs are becoming common, there are a few things you should know to navigate the streets alongside them.
- Don't "Test" the Sensors: It’s tempting to see if a Waymo will honk if you jump in front of it. Don't. Not only is it dangerous, but it also creates data noise that makes the system more "twitchy" for everyone else.
- Report Recurring Issues: Waymo actually listens to community feedback. If a specific intersection is causing the cars to honk or stall, reporting it via their support channels usually results in an engineer reviewing that specific "geofence" and adjusting the behavior.
- Watch the Front Wheels: If you're wondering if a Waymo is about to move or honk, look at the tires. The AI often "pre-steers" or micro-adjusts the wheel angle before it actually moves, which is a tell-tale sign it’s about to execute a maneuver.
- Understand the "Buffer": Waymos require more personal space than humans. If you're tailgating one or pulling too close to its bumper at a light, you're much more likely to trigger a defensive honk or a complete vehicle stall.
The "honking wars" were a funny, slightly annoying blip in the timeline of autonomous transport. They showed us that while the hardware is nearly perfect, the social etiquette of driving is still something the machines are trying to learn. Next time you hear a stray honk from a driverless car, just remember: it's not angry, it's just trying very, very hard not to scratch its paint.