The Advanced Snow Plow system that Caltrans used as a test on Interstate 80 near Donner Summit had four miles with embedded magnets. This cost about $25,000/mile in '98.
> The trucks have two GPS receivers mounted atop the cab. These receivers cost about $10,000 each, Shankwitz says. "That's probably why this hasn't been deployed in many other areas; it's just too expensive and most applications do not require that level of accuracy."
> The two-centimeter accuracy actually comes from a third receiver -- a high-precision, stationary ground-based receiver perched atop a microwave communications tower in nearby Valdez. It's accurate to within millimeters and it acts as reference receiver for the plow-mounted systems.
I don't see this being standard on self driving cars.
It appears that if it doesn't know where the lanes are, it drives in the middle of the road. If someone turned onto the street from 0:35 to 0:42 there would have been a problem.
I'm still waiting to see how an AI would handle Figure 5-1 from that. And no, the snow plow's solution of burying magnets in the road isn't practical (Cost of infrastructure installation for the test sites is approximately $11,000 per kilometer ($17,000 per mile), including surveying, installation, and magnets).
That's been done, in the form of magnets driven into holes punched in the pavement. Early systems just followed the magnets, but today, they'd just be used as an additional hint. It's quite possible that we'll see those in areas with heavy snow. Volvo has been testing this.[1] One of Volvo's arguments is that magnets are also useful for snowplow guidance. Heavy plows often chew up the infrastructure when snow is heavy enough that the road isn't visible. In some areas, poles are placed alongside roads so the plow drivers can tell where they're supposed to be plowing. Sometimes this works.
Since roads where it snows are always getting torn up and repaved, if automated cars do become widespread, it seems entirely feasible and realistic to line major roads on each side with radio reflectors or some other cheap system that can keep automated plows from driving off the road.
The real problem is the cost of the automated plow itself. A 10-wheel plow with salt feeder isn't exactly cheap to run with or without a driver.
> Developed by researchers at the University of California at Berkeley, the Advanced Rotary Plow (ARP) uses a network of magnets embedded along the roadway to guide the massive snow-spewing machine along the Interstate in zero-visibility conditions -- like a blinded pilot flying on instruments. Meanwhile, an onboard array of sensors sniffs out obstacles -- such as abandoned cars, hungry cows, napping yetis, or whatever -- that may lie hidden beneath the deep snows.
> This ASP Human-Machine Interface is mounted on the windshield. Some of the worst visibility conditions on the planet can be overcome with the aid of the ASP cab-mounted display, which receives its data from the plow's collision-warning system. Radar sensing assists human sight to find the road and obstacles that may be in the way of the plow.
The MN version is GPS based while the CA version was magnet based.
> California suffers from extremely wet and heavy snowfalls in their mountainous terrain. Snowfalls of 4 to 5 feet during a single storm are not uncommon. This wet, heavy snow forces snowplows to operate at relatively low speeds. Because of these conditions and the previous experience the California team (CalTrans, University of California at Davis, and the University of California at Berkeley’s PATH program) has with magnetic based vehicle guidance, the California team focused on the application of magnetic vehicle guidance to this snow removal problem. In addition to the application of the magnetic technology, the California team developed driver displays designed to convey information provided by the magnetic lane guidance system to the driver.
> In contrast to California, issues with snow removal in Minnesota arise because of high winds which can blow light, dry snow at high rates across vast stretches of prairie. This blown snow can create significant drifts which must be continuously cleared in order to keep roads open. Under these conditions, snowplow operations are required to run at relatively high speeds to avoid road closures because of drifting. Because of these weather and geographic conditions, the Minnesota team focused on DGPS based solutions to this particular snow removal problem. The Minnesota team also developed driver displays designed specifically to convey lane keeping and collision avoidance information provided by the on-board systems.
The modern version is that Volvo has proposed putting magnets, in the form of nails, into pavements. This is to provide a hint of where the lanes are under snow. It also provides guidance for snowplows. These would probably be driven in by the same machines that stripe lanes. This is an old idea from the early days of automatic driving, but today they'd just be viewed as a hint, not something to be followed blindly.
There are areas where high visibility snow stakes are placed alongside highways for driver and snowplow guidance. Hokkaido puts large downward pointing arrows over snowy highways to mark the shoulder.[1]
Wire guidance systems have been around for years, for industrial robot vehicles. GM put them on their test track for Firebird III in the 1960s. But it's no longer necessary to have even that much infrastructure.
Volvo was looking into that. They want to drive magnetized nails into pavement on some Swedish highways to provide a lane reference. That can be sensed through snow, and snowplows can be equipped to sense it, so it has uses beyond self driving.
"I don't fully understand why more effort is not put into a hardware solution, where roads are simply marked up for self-driving vehicles, e.g. magnets lining the lanes or something like that."
Volvo is plugging for magnets in roads in Sweden, so they can find lanes in the snow. It might happen, because it can also be used for snowplow guidance.
In heavy-snow areas, posts, poles, and even over-road arrows (Japan uses this in Hokkaido) are placed to provide guidance. It's not intended to replace vision and LIDAR, just as additional guidance hints for bad conditions.
"Today, we know we can’t put magnets in the pavement everywhere for cars to follow..."
Why not?
As someone from a Midwestern state, I fear that all the self-driving car development in California is going to miss the important edge cases we experience here. Snow, plows, salt, dirt, heavy rain, etc all destroy the visibility of lane lines.
What we need is something that can be a marker for cars that doesn't require line of sight, or else self driving cars aren't going to be able to navigate at the lightest snowfall.
Are self-driving snow plows realistic, even if just on highways? Would such plows eventually be more affordable, be able to run almost 24 hours a day and mean that more road is cleared?
(It never snows where I live so plowing or driving on snow is an alien concept to me.)
That's how GM did automatic driving for Firebird II and III in the 1960s.
Volvo's solution for snow is to drive magnets in the form of nails into the pavement along lane centerlines. They suggest that this can provide guidance for snowplows as well as assist autonomous vehicles.
Lane marking in areas of heavy snow is hard. Some areas put up plastic posts along the roadside. Japan puts up arrows hanging over the road in parts of Hokkaido.
This also seems like a fantastic addition to snow plows. They could even serve as a great testing platform--still human driven, but with tons of real world snowy road data. Fast forward a few years and autonomous snow plows will be really nice--an army of plows working through the night and even during the worst storms.
Sure it is. Volvo developed a system where magnetized nails are driven into the pavement to mark the center of lanes. It's an additional hint, for when the visual, LIDAR, and GPS systems could use a little help. As in heavy snow. Volvo also points out that it's useful for snowplow guidance.
AGVs have been using wire guidance for years. You cut a notch in the floor, put in a wire, and fill in the notch. That's the technology GM used for the Firebird demo cars in the 1960s.
> I think the reality here is that we don't have the fuzzy logic and AI to handle snow covering up lane markers...
True, but improved AI isn't the only way to address such problems. For instance, thermal cameras can see through light snow, so those may become standard. Also, something like RFID embedded an inch or two below the road surface could serve as marker enhancers. If all else fails, GPS and highly accurate maps can stand in for road markers in many areas. Besides, snow won't be as much of an issue if self-driving snowplows get started shortly after snowfall begins.
Volvo are just trying to get someone else to provide the infrastructure for self driving.
I live in Norway, the poles at the side of the road are not just for the snowploughs, they are very helpful for human beings too. Magnetic nails embedded in the road are not at all useful to humans and are just more stuff to maintain, especially in an environment where simply maintaining centre and edge markings is a difficult and time consuming job.
The full description of the system can be read at https://path.berkeley.edu/sites/default/files/advanced_snowp...
Alaska uses GPS for their precision plowing - https://www.truckinginfo.com/329914/how-alaska-dot-uses-gps-... . Note that to get the 2" precision you need high quality GPS receivers.
> The trucks have two GPS receivers mounted atop the cab. These receivers cost about $10,000 each, Shankwitz says. "That's probably why this hasn't been deployed in many other areas; it's just too expensive and most applications do not require that level of accuracy."
> The two-centimeter accuracy actually comes from a third receiver -- a high-precision, stationary ground-based receiver perched atop a microwave communications tower in nearby Valdez. It's accurate to within millimeters and it acts as reference receiver for the plow-mounted systems.
I don't see this being standard on self driving cars.
That said, ground penetrating radar is being looked at and appears to be a lower price point. https://phys.org/news/2016-06-vehicles-high-precision-advers...
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