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Comment by duck | Hacker News Reader

The cars still need to learn how to handle snow-covered roads

That is going to be hard to pull off. For places that get a lot of snow, often you can't even be sure if you're on the road or not.

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In theory autonomous care would be able to include a number of other factor to decide if they are on the road or not. Including, GPS, wifi signals, the grade of the road, the texture of the road, etc.

What about situations where lanes have been plowed off-center? Even the most accurate GPS and accelerometers aren't going to help the vehicle understand that the appropriate path has been shifted.

The car would still factor in the 3d analysis of nearby objects so assuming the use technology that works in heavy snow/rain fall they wouldn't run into anything.

A snow-covered road is a situation where:

  1. Road indicators are difficult to identify
  2. Roadway has less traction than usual
  3. Humans are having emotional reactions (joy, terror) which impacts their processing abilities.

3 is mitigated by design. 1 is a sensor issue, it's also a problem that very accurate GPS can solve.

There are many causes of slick road surfaces, from snow and ice to excessive water, spilled materials, collision debris, and low-quality roadways (dirt and gravel roads). Driving in reduced-traction situations shouldn't be an edge-case.

Actually the problem with snow is specific to Google's approach and is not limited to snow, but to all changes of the environment. They use the 360 degree LIDAR (Velodyne) and drive multiple times over each street in order to create a 3D map which is used for localization after that. Therefore the snow changes the layout of the environment significantly and localization stops working, which in turn makes functions like lane keeping, car detection, traffic light detection etc impossible. This will also happen if the environment changes a lot in another way.

This brings up another question: How will these cars react when a street is blocked and unpassable, due to heavy snowfall (unplowed), heavy rainfall over the street, mudslides & rock slides, etc?

What about where a street has parked cars on both sides and just enough room for one car to go through the middle of the street - one of the narrow city streets where drivers have to wait in the intersection for oncoming cars - will these autonomous cars wait and let drivers through, or will they get stuck?

Personally, I can think of lots of edge cases that will be interesting to see answers to. For instance, a 4-way stop - we know how to handle that easily, and can overcome someone jumping out of turn, again, quite easily.

More importantly - who will be maintaining all the traffic changes? An example - a section of Interstate or road is closed for months, whether by damage or construction. And then, when it's clear again?

I'm interested in seeing how these things play out.

The 4-way stop was something they had to change from the ideal setup. The google car was obeying the law and waiting its turn and never getting it. They made it get more aggressive the longer it waits and now it gets through them just fine.

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