12 votes

Why autonomous trucking is harder than autonomous rideshare

25 comments

  1. [20]
    largepanda
    Link
    What if we put the trucks on some sort of closed roads? They could be run far more efficiently, no collisions to worry about except ones that would already be known. You could even run them on...

    What if we put the trucks on some sort of closed roads? They could be run far more efficiently, no collisions to worry about except ones that would already be known.

    You could even run them on metal tracks, which would be far more efficient than rubber tires on asphalt. Actually, you know how some trucks have two trailers? What if we give them more like 100 trailers in this system? Then you wouldn't need to coordinate so many tiny worker drones, instead just handfuls of large ones.

    Oh wait I'm describing trains again aren't I?

    24 votes
    1. [19]
      skybrian
      Link Parent
      This is easy snark, but it's uninformed. We have freight trains and they work very well, but roads go a lot more places than trains. Most businesses don't have a rail siding leading to them. More...

      This is easy snark, but it's uninformed. We have freight trains and they work very well, but roads go a lot more places than trains. Most businesses don't have a rail siding leading to them.

      More about trucking in this article:

      Trucking accounts for 80.4% of US freight costs and is 4x larger than rail, air, and ocean freight combined. [0] My favorite statistic: 95% of fruits and vegetables in the US are transported by truck. [1]

      Compared to other forms of freight, trucking is neither the cheapest nor the quickest. But it carries two distinct advantages - infrastructure and flexibility.

      20 votes
      1. [16]
        Ashelyn
        Link Parent
        The flexibility part I get, but the infrastructure argument is the direct result of spending decisions that can be shifted at any time, given enough public support. While it's true that a...

        The flexibility part I get, but the infrastructure argument is the direct result of spending decisions that can be shifted at any time, given enough public support. While it's true that a comprehensive rail network doesn't really exist in the US, nor could one be built overnight, the argument remains that the infrastructure advantage only remains an advantage through ongoing budgetary decisions.

        Last mile delivery is still a problem, yes, but I think it's a bit ridiculous to assume that just because we don't currently have rail running into every strip mall that we couldn't see a future where the vast bulk of freight transportation is done by rail. We'd certainly be able to cut down on a lot of fuel usage and/or lithium extraction going the rail route instead of the one that involves hundreds of thousands of autonomous drones carrying multi-ton payloads.

        17 votes
        1. [15]
          skybrian
          Link Parent
          "Comprehensive rail network" is easy to say, but this is seriously underestimating the practical problems. Railroad crossings are dangerous and slowly being replaced by bridges and underpasses....

          "Comprehensive rail network" is easy to say, but this is seriously underestimating the practical problems.

          Railroad crossings are dangerous and slowly being replaced by bridges and underpasses. Railways are fenced off for safety, with some pedestrian bridges that are still kind of a pain to use. They divide neighborhoods like freeways do - think about what "the wrong side of the tracks" means. People don't like to live next to them; you get noise and no advantage since you can't use them directly.

          Railroads are great, but we don't want them everywhere.

          As an example of the difference in scale and flexibility, replacing school busses with railroads in rural areas would be ridiculous.

          18 votes
          1. [8]
            scroll_lock
            (edited )
            Link Parent
            At-grade crossings are dangerous, but there exists no world in which they are more dangerous than highways, including one in which automated trucks exist. The number of humans killed and injured...

            Railroad crossings are dangerous and slowly being replaced by bridges and underpasses.

            At-grade crossings are dangerous, but there exists no world in which they are more dangerous than highways, including one in which automated trucks exist. The number of humans killed and injured from freight transport will literally always be higher on a road than on a rail simply because the former mode is uncontrolled and unpredictable; highway freight is coincident with conflicts that rail freight never is.

            The reason at-grade crossings are being (incrementally) replaced with grade-separated crossings has more to do with maximize traffic throughput for the incredibly inefficient vehicles knows as automobiles than safety; the latter is an afterthought. The government pays lip service to safety with its speed limits, but the impetus for most municipalities to fund grade separation is to reduce traffic congestion.

            They divide neighborhoods like freeways do

            This is true but your conclusion is not useful. An extraordinarily viable strategy for constructing a larger scale freight rail network is to build tracks along interstates. The rights of way already exist. The overwhelming majority of long-distance truck shipping already follows interstates. Those goods could much more efficiently, sustainably, and safely be transported by rail for the majority of their journeys. Technically, in most cases, automobile lanes could be removed without creating road congestion, eliminating the need to widen the right of way. In other cases, widening the right of way is permissible because there are no nearby structures.

            10 votes
            1. [7]
              skybrian
              Link Parent
              Well, that's a good question: why don't railroads go the same way as highways? I believe sometimes they do? When they don't, it might be that the railway was there first, or that the highway takes...

              Well, that's a good question: why don't railroads go the same way as highways?

              I believe sometimes they do? When they don't, it might be that the railway was there first, or that the highway takes a route that's not suitable: the hills are too steep or the curves are too sharp.

              The US railway network looks pretty extensive and comparable to the Interstate highway network. And yet, lots of freight goes by truck anyway, and it would be interesting to know why that is.

              5 votes
              1. [6]
                scroll_lock
                (edited )
                Link Parent
                It would be more accurate to say that highways traditionally followed railroads. The railroads enabled population centers to exist. Then the tracks were torn up to build highways between said...
                • Exemplary

                It would be more accurate to say that highways traditionally followed railroads. The railroads enabled population centers to exist. Then the tracks were torn up to build highways between said population centers. Lots of tracks have survived though and many are still in active commercial use.

                However, new railroad construction slowed down significantly in the 20th century as funding was redirected toward highway construction to population centers that didn't previously exist. Those new highways don't have parallel rails because the government was not interested in subsidizing rail infrastructure. That gave trucking a monopoly over many population centers that should have been served by rail.

                As usual, the reason is not really geographical but rather political. In general, freight trains do not require curves with large radii as they run at slower speeds than highways. Of course there are places where highways are suitable but railroads aren't (at least for slow, heavy diesel freight trains), like mountain passes with extremely steep grades. In these places, the railroad will often depart from the highway ROW. However, these places are not populated, so a temporary departure from the ROW to avoid having to dig a tunnel is usually not disruptive. The majority of such routes can easily feature parallel tracks.

                Brightline West is leasing highway ROW in California and Nevada for its new HSR project for this reason: it's less disruptive to landowners, requiring less property acquisition or eminent domain, so it's cheaper. Those trains will actually travel in the median for most of the route. Passenger trains can take steeper grades.

                The US railway network looks pretty extensive and comparable to the Interstate highway network. And yet, lots of freight goes by truck anyway, and it would be interesting to know why that is.

                It's comparable to the interstate road network, but not the combination of the state and interstate networks. Many places are effectively unserved by all rail. This is by far the biggest issue: many customers can only physically receive shipments by truck. With that said, intermodal shipping can still be highly effective. You can see a map of tonnage transported by rail vs. truck (p. 11 of the PDF; p. 6 of the document) from the Government Accountability Office. This data is from 2007, but it hasn't changed much since then. In many regions, there are trucks but no trains; in others, there are both but trucks dominate. (This report is about public/non-commercial costs, but that map is great.)

                In general, rail becomes more economical the more goods you're shipping. Railcars are usually physically heavier than trucks, which means some of the weight the locomotive is pulling are the traincars themselves, not the goods. However, trains can have 200+ cars while a truck has exactly 1, so with enough capacity, sending your goods by rail evens out. Per-ton, freight trains blow trucks out of the water (so to speak), but if you're shipping things in small quantities or very short distances, trucking wins. This is exacerbated by a lack of rail-equipped receiving facilities. Even with a cheap intermodal process, our infrastructure often favors trucks.

                One thing you won't see in an infographic anywhere is that railroad workers are unionized at a higher rate than truck drivers, most of whom are contractors. For this reason, freight rail compensation is high: around $143,000/yr. Some truck drivers have earnings like that, but it's rare. You would have to specialize in radioactive goods or something. :P Most truck drivers earn more like $70,000/yr (optimistically). Part of this, again, is because train people are unionized and relatively few truckers are. Turnover in trucking is also rather high, which keeps costs down. The low cost of labor contributes to competitiveness: certainly not as much as infrastructure or economies of scale, but it's relevant.

                Note: freight railroad tracks aren't publicly owned so there are large regions with only one or two railroads. Companies here are called "captive shippers." Trucking may technically compete intermodally, but many rail-dependent shippers exist due to situations where trucking isn't economical (like bulk raw materials... not something to send by truck). However, unfinished goods just aren't as profitable as finished goods, so the overall profit margin from rail is not that high even though many captive markets exist.

                I will end with this note from the GAO:

                GAO’s analysis shows that on average, additional freight service provided by trucks generated significantly more costs that are not passed on to consumers of that service than the same amount of freight service provided by either rail or water. GAO estimates that freight trucking costs that were not passed on to consumers were at least 6 times greater than rail costs and at least 9 times greater than waterways costs per million ton miles of freight transport. Most of these costs were external costs imposed on society. Marginal public infrastructure costs were significant only for trucking. Given limitations in the highway, rail, and waterway economic, financial, technical, and environmental data available for the analysis, GAO presents conservative estimates.

                Trucking is more profitable than rail because it passes on most of its costs to the public, just not directly to the shipper. Therefore, it is often cheaper for companies to pay for truck shipment, and the sticker price for consumers to buy those goods than if they were shipped by rail. However, those consumers pay significantly more in taxes to recoup the infrastructure and social costs incurred by trucking.

                5 votes
                1. [5]
                  skybrian
                  Link Parent
                  I'm not sure what to do with that sort of comparison, though. The Biden administration is big on passenger trains, and port facilities are getting some major government investment. That does...

                  I'm not sure what to do with that sort of comparison, though.

                  The Biden administration is big on passenger trains, and port facilities are getting some major government investment. That does include some rail improvements.

                  But in general, it seems unlikely that shipping by truck will decline due to better railways. The US has the largest rail network, but it's dropped significantly in size and seems unlikely to get a lot bigger again.

                  2 votes
                  1. Malle
                    Link Parent
                    Looking at length of rail per country isn't really a helpful measure for knowing or comparing how well-connected a country is for shipping by rail. Size, geography, demographics, etc. all play a...

                    Looking at length of rail per country isn't really a helpful measure for knowing or comparing how well-connected a country is for shipping by rail. Size, geography, demographics, etc. all play a role. That's not easy to quantify or summarize.

                    The article you linked lists measures of railroad density (where the US ranks 50th) and railroad length per capita (where the US ranks 33rd). These are not perfect measures either for this purpose, but at least they'll give a more nuanced picture.

                    5 votes
                  2. [3]
                    scroll_lock
                    (edited )
                    Link Parent
                    I will remark that the European Union is currently investing in continent-wide railroad freight infrastructure with the specific purpose of inducing a modal shift away from trucks and toward rail....

                    I will remark that the European Union is currently investing in continent-wide railroad freight infrastructure with the specific purpose of inducing a modal shift away from trucks and toward rail. This is because the social and environmental costs of excessive trucking are significantly higher than the price of the infrastructure upgrades necessary to encourage more freight to be shipped by rail. The EU has identified a problem and has chosen to do something about it instead of sinking into apathy.

                    As before, these decisions are strictly political. There is no inherent force of nature ensuring that the United States' freight rail network is "unlikely" to increase in size. The government could choose to incentivize such things if it decided that was a priority. Currently, it chooses (voluntarily) to prioritize truck infrastructure, but that is informed more by inertia than utility. A pivot requires constituents to understand that a freight industry dominated by trucking is problematic for safety, environmental, and financial reasons; with that understanding, it becomes politically easier to invest in rail.

                    Biden is big on Amtrak specifically and friendly to rail in general, but the Bipartisan Infrastructure Law was a one-time thing. A better freight rail system would include at least some public tracks owned and operated by the government, as well as consistent funding for those services in the way highways currently receive funding. It would have to be a law that isn't time-bound like the BIL, which ends in 2026.

                    2 votes
                    1. [2]
                      skybrian
                      Link Parent
                      I'd be interested in reading more about what the EU is doing. What have you read?

                      I'd be interested in reading more about what the EU is doing. What have you read?

                      1. scroll_lock
                        Link Parent
                        At a high level, the EU adopted a vision for a Trans-European Transport Network (TEN-T) in 1996 and has stuck to it since then. This network is multimodal but has a particular focus on railways...

                        At a high level, the EU adopted a vision for a Trans-European Transport Network (TEN-T) in 1996 and has stuck to it since then. This network is multimodal but has a particular focus on railways and ports (note that the vision does not mention highways first). It consists of ten distinct but interlinked corridors connecting different regions. Under this umbrella, there exist mode-specific networks like the Trans-European Rail Network, but connections are designed to be plentiful and intermodal.

                        An example of a project that's been making some headlines is the Turin–Lyon high-speed railway, which will include a 57.5 km tunnel through the Alps (not to be confused with the existing Gotthard Base Tunnel, which supports a north-south route and is 57.1 km long). The laity care about it because it will support high(er)-speed passenger service and oooh longest tunnel in the world. Companies care about it because it will enable much faster and more reliable freight service. This particular project is one which is being funded in part for the purpose of taking trucks off the road, both for congestion and environmental purposes. Safety is not a motivator, but is still a real benefit.

                        2 votes
          2. [4]
            boxer_dogs_dance
            Link Parent
            Many cities, including Oakland where I live, used to have trams and light rail which were good for getting from residential neighborhoods to central locations. I think increased number and safer...

            Many cities, including Oakland where I live, used to have trams and light rail which were good for getting from residential neighborhoods to central locations.

            I think increased number and safer railroads should be part of transportation strategy.

            5 votes
            1. [3]
              skybrian
              Link Parent
              Yes, light rail and freight trains are different. Shipping containers are too big for many business deliveries anyway. I can imagine some sort of "light freight rail" but someone would have to...

              Yes, light rail and freight trains are different. Shipping containers are too big for many business deliveries anyway. I can imagine some sort of "light freight rail" but someone would have to invent it.

              I'm not sure the rails are necessary, though? San Francisco has trolley busses that seem to work well? There was apparently a study about how to improve them:

              SFMTA's existing trolley buses can already go a few miles on small battery packs designed for emergency use. "They can only run two miles off wire," said Lantsberg. His group is advocating for using trolley buses that have more substantial battery packs than the existing fleet and that can be charged while they're running in service. Then the buses can go many miles into non-electrified territory as well. They can also run when sections of wire are under maintenance.

              2 votes
              1. [2]
                scroll_lock
                (edited )
                Link Parent
                The use-case for sending an intermodal container directly to a business very much exists. Manufacturers and warehouses benefit from bulk goods, including raw materials. Businesses that interface...

                The use-case for sending an intermodal container directly to a business very much exists. Manufacturers and warehouses benefit from bulk goods, including raw materials. Businesses that interface directly with consumers (like restaurants) typically don't, but those can be served by any number of means.

                It isn't advisable to send freight trains with ISO containers down city streets that feature "light rail" tracks because such massive vehicles simply do not belong near Vulnerable Road Users. It would be stupidly dangerous to send a 12,000-ton freight train down a light rail line. Really this is not different than 18-wheelers carrying containers on city streets, which are similarly dangerous (but we pretend they aren't). The best vehicle in an urban setting is a half-sized truck or potentially an electric delivery bike. In each case trans-shipment is required at a facility outside the city core... a facility that could be served by heavy rail.

                Pedantic note: the distinction between "light rail" and "heavy rail" is relatively arbitrary. It's a mushy set of categories and many street-running "light rail" cars aren't particularly light. Many (most?) legacy light rail lines in the US were constructed to a heavy rail standard because they used to take freight shipments too. As long as the tracks are standard gauge, they can theoretically accept the same rolling stock, which means they can accept the same cargo. The engineering concern is whether the bed is able to distribute the force of the train at any particular point point on the track. Some light rail systems also use weird wheels.

                In practice, there might be conflicts with signaling systems, and more importantly a two-way track doesn't work for systems that run coincident trains at different speeds (you need four tracks for that, or someone's going to be waiting). The corridors in the US that share light rail and freight traffic typically split operations by time of day. The New Jersey Transit River Line is the only example I remember offhand. Conrail runs freight trains along that route at night.

                2 votes
                1. skybrian
                  Link Parent
                  Yes of course, it would have to be a different kind of shipping, more comparable to a UPS truck.

                  Yes of course, it would have to be a different kind of shipping, more comparable to a UPS truck.

          3. [2]
            JCPhoenix
            Link Parent
            Along those lines, over on reddit, I recently got an unexpected, out-of-the-blue invitation to a subreddit that focuses on the Brightline passenger service in Florida. No idea why I was invited,...

            Along those lines, over on reddit, I recently got an unexpected, out-of-the-blue invitation to a subreddit that focuses on the Brightline passenger service in Florida. No idea why I was invited, but that's beside the point. Anyway, the sub is specifically about accidents and deaths attributed to Brightline. And surprisingly, there are lots.

            The AP analysis shows that Brightline averages about one death for every 35,000 miles (56,000 kilometers) its trains travel, three times worse than the next mid-size or major railroad. According to police reports examined by the AP, investigators determined most of those killed have been suicides, drivers maneuvering around crossing barriers to try to beat the trains, or pedestrians who were intoxicated or mentally ill.

            Source (Feb 2022)

            Part of the issue seem to be that Brightline, which is higher-speed rail, goes through lots of built-up areas and has lots of at-grade crossings. The other issue is that many of the accidents seem to be foolish people who think they can outrun the train and go around the crossing arms. Apparently there were two separate deadly accidents involving Brightline last week at the same crossing.

            I'm also reminded of 2022, when Amtrak was involved in two separate crashes at at-grade crossings, basically back-to-back. One in Missouri, the other in California. Somewhat different from Brightline, since these happened in rural areas where there weren't modern crossing safety devices. Still, it's an issue.

            I'm pretty pro-train. I've taken long-haul Amtrak many times, love it, and wish I could take it to more destinations across the country. I enjoy taking light-rail and rapid transit when I'm visiting other cities (my city has neither, sadly). I want more trains! But these incidents definitely give me some pause. Not that we shouldn't pursue more rail, but that we have to do it right, like utilizing grade separation. Which I know is expensive. Even if it's not the railroad company's fault, rather it's people being dumb around massive tons of metal moving at high speeds, safety has to come first. And some locations just may never be good for rail because the safety concerns are too high (and costs too prohibitive).

            3 votes
            1. scroll_lock
              Link Parent
              The federal Bipartisan Infrastructure Law funds a Railroad Crossing Elimination Program intended to improve operational efficiency and safety. Thanks exclusively to funding prioritized by the...

              The federal Bipartisan Infrastructure Law funds a Railroad Crossing Elimination Program intended to improve operational efficiency and safety. Thanks exclusively to funding prioritized by the 117th Congress and President Biden, the Federal Railroad Administration (FRA) is issuing billions of dollars to address this specific issue.

              The reason many passenger and freight railroad tracks are limited to low speeds is because of at-grade crossings. It is obviously unsafe to have a train traveling at high speeds along a route that is technically not completely access-limited. Most railroad trespassing deaths are from cars driving onto the tracks at crossings and killing the passenger and/or causing a derailment; a minority are from pedestrians on the tracks. Minor derailments are not newsworthy, but a particularly nasty derailment can destroy rolling stock and bankrupt a passenger railroad (legal fees), as well as harm its reputation. That ultimately has a great but hard-to-measure capital cost in reduced railroad revenue, higher insurance costs (an inefficiency), and less rail ridership (environmentally and socially costly for various reasons). So the benefit to grade-separated crossings is not just improving safety for its own sake, but also improving operational efficiency and reliability. It also directly improves automobile throughput, including for freight trucks.

              These combined benefits make the investment financially worthwhile in the majority of cases. I think that human life is the most important factor here by far, but efficiency is a more quantifiable metric. Even in the agricultural and sparsely populated sections of the Central Valley, California High-Speed Rail is a grade-separated route for this reason: they want reliable 220 mph service. Safety legally underpins that limitation but it is ultimately a business decision and not an ethical one from the perspective of an operator.

              6 votes
      2. [2]
        largepanda
        Link Parent
        Absolutely, most places don't have rail sidings. No-one is realistically suggesting to get rid of trucks completely. Keep the trucks between the railyards and the local businesses. Stop sending...

        Absolutely, most places don't have rail sidings. No-one is realistically suggesting to get rid of trucks completely. Keep the trucks between the railyards and the local businesses.

        Stop sending trucks across the country. Last mile delivery will remain trucks for a very long time, but the idea of "last mile = trucks, therefore every mile = trucks" is absurd.

        This solves the issue of autonomous trucking by eliminating nearly every use case for it. If trucks are limited to being local runabouts instead of long haulers, that's work that already has to be done by humans, you can't have a fully autonomous truck trying to deliver to the mall. Truckers can gain intimate knowledge of their local roads rather than constantly driving between unseen towns, making them more familiar and safer.

        7 votes
        1. skybrian
          Link Parent
          I do think it's a good question why intermodal/multimodal shipping isn't used more.

          I do think it's a good question why intermodal/multimodal shipping isn't used more.

          6 votes
  2. [3]
    skybrian
    Link
    I wonder if simply driving slower would help? A self-driving truck could drive more slowly and make up for it by driving at night. Unfortunately we don't have a whole lot of roads where this could...

    I wonder if simply driving slower would help? A self-driving truck could drive more slowly and make up for it by driving at night.

    Unfortunately we don't have a whole lot of roads where this could be done without annoying other drivers.

    4 votes
    1. [2]
      Sodliddesu
      Link Parent
      This was my exact thought... Or just use trains instead. If driverless rideshare is easier, driverless last mile delivery should be easy too - so just build out the trains and we don't have to...

      This was my exact thought...

      Or just use trains instead. If driverless rideshare is easier, driverless last mile delivery should be easy too - so just build out the trains and we don't have to deal with them on the highways!

      4 votes
      1. skybrian
        Link Parent
        No, it's not that easy. See my other response. But sometimes containers get carried by train part of the way - that's called either "intermodal" or "multimodal" shipping. A good question would be...

        No, it's not that easy. See my other response.

        But sometimes containers get carried by train part of the way - that's called either "intermodal" or "multimodal" shipping. A good question would be why it isn't used more for land transportation.

        1 vote
  3. Carrow
    Link
    I'd like to see the author source this claim, as it contradicts the work I do with lidar data daily. We obtain very high precision data of ground and grounded features from helicopters in rather...

    Lidar sensors provide trustworthy 3D data because they take direct measurements based on physical principles. They have a usable range of around 200–250 meters, plenty for city driving but not enough for every truck use case. Lidar detection models may also need to accumulate multiple scans/frames over time to detect faraway objects reliably, especially for smaller items like debris, further decreasing the usable detection range.

    Note that some solid-state lidars claim significantly more range than 250 meters. These numbers are collected under ideal conditions; for computing minimum sensing capability, we are interested in the range that can provide perfect recall and really great precision. For example, the lidar may be unable to reach its maximum range over the entire field of view, or may require undesirable trade-offs like a scan pattern that reduces point density and field of view to achieve more range.

    I'd like to see the author source this claim, as it contradicts the work I do with lidar data daily. We obtain very high precision data of ground and grounded features from helicopters in rather non ideal scenarios. We're able to accurately model systems within inches (the limit here is really on processing time and accuracy of other physical properties not associated with the lidar).

    Admittedly, these are rather expensive sensors, I'm not sure how much exactly. We also have to calibrate our data before modeling, which involves handling noise and synchronizing multiple flight lines. And this scenario is very different from how we use lidar, so perhaps those confound variables too much (ie need of immediately usable data), but the factors the author mentions are ones we already deal with on a much larger scale at far greater distances with excellent precision.

    3 votes
  4. skybrian
    Link
    From the article: ... ... ... ...

    From the article:

    The required sensor capability for an autonomous vehicle is determined by the most challenging scenario that the vehicle needs to handle. A major challenge in trucking is stopping behind a stalled vehicle or large debris in a travel lane. To avoid collision, the autonomous vehicle would need a sensing range greater than or equal to its stopping distance.

    ...

    Passenger vehicles can decelerate up to –8 m/s². Trucks can only achieve around –4 m/s², which increases the stopping distance and puts the sensing range requirement right at the edge of what today’s sensors can deliver.

    ...

    [On the freeway,] [s]topping in lane becomes much more dangerous with the possibility of a rear-end collision at high speed. All stopping should be planned well in advance, ideally exiting at the next ramp, or at least driving to the closest shoulder with enough room to park.

    ...

    The features that make freeways simpler — controlled access, no intersections, one-way traffic — also make “interesting” events more rare. This is a double-edged sword. While the simpler environment reduces the number of software features to be developed, it also increases the iteration time and cost.

    ...

    Does this mean driverless trucking will never happen? No, I still believe AV developers will overcome these challenges eventually. Aurora, Kodiak, and Gatik have all promised some form of driverless deployment by the end of the year. We probably won’t see anything close to a million-mile deployment in 2024 though. Getting there will require advances in sensing, machine learning, and a lot of hard work.