Comment by hncbw02z5a
3 days ago
Winter is the real test here. Worked on lidar perception for a bit and falling snow throws returns everywhere, plus once the lane lines are under slush everyone just drives in the ruts the car ahead made. Curious how they handle those unofficial lanes.
As a driver in places where it snows... I'm curious about how it will handle:
1. Fresh unplowed snow where there are no lane markers visible.
2. Significant banks that take up half a lane with two lanes in each direction.
3. Ice (often one doesn't start going through an intersection on a green until you're 100% sure that every car has cleared - I've been on both sides of this, where you don't go because there's a car sliding through, and the car sliding through because slick ice doesn't care about brakes)
4. Hard braking (the "drive slow and use the brakes lightly for a long while")
5. Cold car things. Electric battery life in the cold (heater for the passengers). Wipers frozen to the windshield. Accumulation of snow on the window. Excess snow on top of the car (considered an insecure load).
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Tangent for the "how do you handle lanes when you can't see any" ... old school approach: https://ieeexplore.ieee.org/document/833362
> Driving a snowplow during whiteout condition is one such example. In order to improve the safety and efficiency of the snow removal operation, a supplemental steering guidance display was proposed and instrumented in a Caltrans snowplow. The guidance information was calculated based on the magnetic markers embedded under the roadway. Operations were successfully conducted on a 6.25 km freeway over Donner Summit on Interstate 80 in California during the 1998-1999 winter season.
https://ahmct.ucdavis.edu/advanced-snow-plow
> 1. Fresh unplowed snow where there are no lane markers visible
Forget unplowed snow. Often in Calgary where I live there's no lane markers visible under the snow for months at a time, even if it's plowed regularly
When all an account posts is claims of first-hand experience with various unrelated technologies, the strategy becomes a bit too obvious: https://news.ycombinator.com/threads?id=hncbw02z5a&next=5009...
Thanks for pointing it out. The phrasing made me slightly suspicious, but those kinds of posts are often hard to detect in isolation.
True. But don't most people drive in the tracks of the car ahead? I know when it snows people sometimes make a three-lane highway into a two-way "rut railway" road, and make do.
They've been doing test runs here in Minneapolis for more than a year. You're right that it's a challenge, but I bet they'll do fine after a couple years of refinement.
Yep, full launching in Denver just recently as well.
They linked to https://waymo.com/blog/2025/10/creating-an-all-weather-drive... discussing the snow mitigations all the way from software down to the built-in heaters on the sensors.
I worked on perception systems five years ago and we had de-noising algorithms that are much better now. We would never have dared to drive in obscured lanes, but I assume Waymo’s high resolution maps and sensor fusion are extremely good, but yeah, are the vehicles going to plow through the unofficial lanes?
I have zero idea about lidar operational capabilities, but can you heat them to stop snow and ice from piling up?
Parent is referring to snow in the environment, not on the lidar itself.
When snowing in Toronto you usually cannot see the painted lines on the road, there's just the lines from cars driving through the snow that you follow. Sometimes two lane roads become an unofficial one lane road depending on what feels safe.
The falling snow also bounces the laser pulses(?) back at the lidar. Snow fall can be pretty heavy and make it difficult to see objects far ahead. Not sure how well their handling of rain ports over to snow, but it will be interesting to see!
Damn, you guys have it hard over there
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Afaik the already do this. But another problem is that falling snowflakes reflect lidar pulses and heating doesn't help in that case
that's in the FAQ. They say they have sensor cleaning tech. But they aren't launching until 2028 so 2 winters of testing should tell.
They will also need mother nature to co-operate. Last winter was brutal in terms of snow, we barely had any snow the year before that!
That's one of the reasons lidar will prove to be a dead end for this application. It's a temporary enabling technology on the path to the simpler multiple camera based solution.
Best approach would be to use both lidar and cameras. They compliment each other
No, in the limit where everyone has lidar they end up stepping on each other too. Being a totally passive sensor system is a major benefit for mass deployment, on top of the cost advantages.
Lidar is cool when you want to get a point cloud from a fixed location, or dealing with perfectly uniform surfaces (which cars don't because humans can't do this either), but beyond that there are better ways to do things.
“Good morning, LIDAR! You’re looking positively radiant today!”
“Why, thank you, Camera! You are doing a wonderful job of seeing everything in your FOV!”
“Ahh, you are very flattering, LIDAR! It’s an endearing quality in you, for sure!”
LIDAR: blushes
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Camera's can't see in the dark. There is no perfect sensor. Waymo relies multiple sensor modalities: Cameras, Lidar, ultrasonics, radar, gps, inertial measurement units.
Also microphones. Don’t forget the (external) microphone sensors.
Cars don't drive in the dark. Roads are usually lit. And every car has its own lights for seeing where you are driving.
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