If you wanted to sum up the state of the self-driving car race, you could do worse than this delightful GIF of a Google self-driving car wiping bird poop off its LIDAR sensor.

That comes courtesy of Bloomberg, which has an in-depth story about the work that Waymo, Google’s self-driving car company, is doing to transform its self-driving car technology from a research prototype into a mainstream commercial product.

Sometimes, birds poop on a self-driving car’s sensors, making it hard for the car to see where it’s going. Obviously, during testing a Waymo employee can just get out and wipe the bird poop off. But Waymo’s ultimate vision is to not have an employee in the car at all, which means the car needs some way to clean its own sensors when they get dirty.

The fact that Waymo is sweating these kinds of details says a lot about how far the company has come. Google’s self-driving cars reached the point where they could gracefully handle most driving situations several years ago. But to turn the technology into a viable commercial product, “most” doesn’t cut it. The service needs to be able to handle every possible problem that could crop up, from unexpected obstacles in the road to bird poop on a key sensor.

And now, Waymo is sweating those details. Earlier this year, Waymo started offering rides to ordinary families in Phoenix. It’s developing the user interface that will allow passengers to tell the car where they want to go and provide feedback that helps reassure passengers that the car has everything under control.

It’s going to take months — possibly years — of sweating these details before Waymo will be able to take the final step of sending the car out on its own, without a Waymo backup driver in the driver’s seat.

Google’s Waymo seems to be way further along in this process than other companies — though it’s hard to know for sure, since Waymo and its competitors tend to keep details of their self-driving programs a secret. But there are signs that bode well for Waymo. Data released by California regulators showed that Waymo racked up a whopping 97 percent of all miles driven by self-driving car prototypes in the state: 635,868 miles, compared to 20,286 miles for the rest of the industry put together.

Across all states and years, Waymo’s cars have racked up more than 3 million miles of real-world driving experience. That means that Waymo has a lot more experience with real-world problems like bird poop, dust storms, and unruly pedestrians than anyone else in the industry. Which means that their vehicles are more likely to be ready if they experience these problems in the real world.

Of course, it’s always possible that a competitor will find shortcuts that allow it to build safe self-driving vehicles without so much painstaking testing. Tesla, for example, is actively collecting data from the thousands of partially self-driving cars it has already sold to customers, giving it more than a billion miles of data about real-world driving conditions.

But so far, Waymo looks like a favorite to bring fully self-driving cars to market first. No other company has put so much time and effort into identifying and solving the many small problems — like a bird pooping on your sensors — that will have to be solved for self-driving technology to become a mainstream consumer product.

Disclosure: My brother works at Google.