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This is something I often thought about as a child. I didn't imagine self driving cars as they are being developed today. Rather, I thought about what it would

• blunte 9y ago
  The beauty of a fully automated and coordinated system is that vehicles would only stop at the end of a journey. Intersections would be a graceful interleaving of vehicles in all directions. This would conserve a lot of energy that is currently wasted on braking and acceleration, and the passengers have less frustration of being stopped when it is their strong desire to be _going_ somewhere.
  • philrw 9y ago
    CGP Grey did an animation of it here: https://youtu.be/iHzzSao6ypE?t=3m46s https://youtu.be/iHzzSao6ypE?t=3m46s
    • skrause 9y ago
      That video is just full of false assumptions. For example at 0:25 he attributes the delays between cars starting at traffic lights to bad reaction times of humans. No, you start with a short delay because otherwise there is no way to reestablish the safety distance to the car in front of you. Which you still want to have with automated driving because self-driving cars won't solve sudden mechanical failures.
      • the8472 9y ago
        How do you think that safety distance is derived?
  • likeclockwork 9y ago
    How would that handle pedestrians?
    • blendo 9y ago
      Assume your personal device has a "Pedestrian" mode. When turned on, it will broadcast your position and velocity 10 times per second (a "Basic Safety Message", https://www.its.dot.gov/itspac/october2012/PDF/data_availability.pdf https://www.its.dot.gov/itspac/october2012/PDF/data_availabi...) The safety message will be detected by all nearby autonomous vehicles, giving them a chance to slow down or stop while you cross. That's the theory, anyway.
    • blunte 9y ago
      Give pedestrians a route over or under the roads. This is done in many places throughout the world already, and it works well. But even if you allow crosswalks and stoplights, cars can use buffer space in traffic (assuming the road is not saturated) to minimize the stops/starts.
      • skrause 9y ago
        > Give pedestrians a route over or under the roads. This is done in many places throughout the world already, and it works well. It really doesn't. Here in Germany most underpasses built in the car-friendly 60s and 70s are being abolished because pedestrians don't like them.
    • derefr 9y ago
      More pedestrian overpasses? Or maybe the same amount, with all the cars flowing down just a few trunk roads, because nobody is trying to “avoid traffic” by taking a side road.
    • skrause 9y ago
      Or more importantly, cyclists. Because they already share the road with cars.
    • iagooar 9y ago
      Replace pedestrians with self-walking autonomous robots! This way they can sync with the cars and cross the street without a single car having to stop or them getting hit.
• Turing_Machine 9y ago
  The problem with a centralized system is that is a single point of failure. If the central system went out, things would get Very Bad, Very Fast.
  • tyingq 9y ago
    There's probably some version of a peer-to-peer "swarm" that gains some benefits though.
    • Turing_Machine 9y ago
      Yeah, there would be advantages in the cars exchanging data, but you could have that while still leaving the final decisions up to the individual car (rather than being dictated by a centralized controller). That's more or less what ants and bees do -- they exchange information with each other, but each unit is still quasi-independent.
  • nealabq 9y ago
    It doesn't have to be centralized. If you think of the cars as data packets and the roads as cat-6 cables, then you can see how redundancy and alternate routing can be built in.
    • csours 9y ago
      You'd want that protocol to be EXTREMELY collision resistant.
      • Turing_Machine 9y ago
        Right. You don't get an automatic retry with cars.
      • stevekemp 9y ago
        Indeed, and you would also want to avoid fragmentation of packets (cars).
    • 9y ago
• dorfsmay 9y ago
  What's more efficient? What's more resilient? An army all walking at the same pace taking their cues on orders or a crowd of autonomous individual, all adjusting pace etc... Based on their local condition (terrain, speed of who's in front...).
• masklinn 9y ago
  > I would imagine cars all taking off together in unison from a stop at traffic lights Why do you even need traffic lights anymore? Autonomous cars can brake and stop for people who need to go through, and synchronise with one another to organise crossing.
  • Bluestrike2 9y ago
    Even if all cars were fully connected and automated, I don't see traffic lights going away outside specific types of areas (rural areas, etc.). In cities, pedestrian infrastructure is pretty much built around the presence of intersections and pedestrian walkways. To keep pedestrians moving relatively quickly, you need those intersections. And while there are options (elevated pedestrian walkways, etc.), those have their own problems (size, expense, ADA compliance, etc.). If you enforce delays for people to cross, which would be the cheapest option, you've just got a stop light by another name. Make it too annoying for people, and they'll run across when they think there's room. With as cautious as autonomous cars have to be with pedestrians, you'd probably wind up with more traffic delays than what we have now. We already have traffic controller systems, but I'd imagine that vehicle communication would allow them to be even more sophisticated.
    • masklinn 9y ago
      > If you enforce delays for people to cross, which would be the cheapest option, you've just got a stop light by another name. If you go to Germany, or Belgium, cars generally stop whenever somebody gets close to the border between the sidewalk and the road, at which point the pedestrian just goes across (then wait 5 minutes and crosses back because they weren't actually trying to cross the road, they were just a foreigner not expecting this). And these are human-driven cars. This can just be universal policy for self-driving cars. It will necessarily be anyway since they will have to deal with people just running across without warning. > And while there are options (elevated pedestrian walkways, etc.) That would be very dumb, one of the benefits of self-driving cars is that you can significantly scale back the car-centric infrastructure and especially affordances towards drivers, there is no risk of drivers being bothered or annoyed or taking rash decisions, the cars just follow policy which is whatever you want to be, every merge is now a proper zipper at the very end of the merge lane & all that. And wherever that's an option you can just bury the road entirely and keep pedestrians in the sun up top as they did for the centre of the planned city of Louvain la Neuve in Belgium: > one of the main points of the urban design of Louvain-la-Neuve was to make it people rather than automobile centred. As a consequence, the city center is built on a gigantic concrete slab, with all motorized traffic travelling underground. This allows most of the ground level of the city center to be car free. (when they need new accommodations, they expand the slab and build the buildings at the same time) > I'd imagine that vehicle communication would allow them to be even more sophisticated. That's a really sad lack of imagination.
• throwaway2016a 9y ago
  If all cars are autonomous it is more efficient to have two cards approaching at the same time negotiate a speed at which they can safely pass through the intersection without stopping or colliding. Stopping would be a thing reserved for when you get to your destination or a pedestrian gets in the way. It's more efficient that way. The energy needed to accelerate is less than the energy needed to maintain speed. Which of course bring sup the idea of hacking the negotiation so that you always have the favorable outcome. The same way some people try to hack the sensors that turn lights green for emergency vehicles.
• Bluestrike2 9y ago
  It probably depends on what you mean by a centralized system. Right now, autonomous vehicles are being developed with a focus on independent operation. Which makes sense, since early examples will find themselves having to integrate into roads lacking car-to-x (or similar) infrastructure[0] shared with vehicles that lack the ability to share anything. There'll be a transition, but older cars will pretty much always be around. Though I wonder if we'll see retrofit kits making use of OBD-II ports for older cars to give them at least some communications abilities at some point, or even some sort of GPS "box" for even older cars lacking OBD ports altogether. Even when car-to-x and vehicle-to-vehicle communications are standardized with widespread use (and they'll both be usable even with non-autonomous vehicles), I doubt we'll see the sort of centralization with hyper-optimized traffic patterning in the animation linked by philrw. Cars will still be able to share information, and make use of it to change their behavior for minimal disruption of traffic flows. They'll talk to infrastructure, and probably even make use of relays well ahead of key infrastructure elements (ramps, bridges, construction zones, etc.). But I wouldn't consider it "centralized" in that situation. For example, a car is entering an on-ramp. Local infrastructure could communicate that fact, as well as other information about the car to traffic approaching the on-ramp. Is it a heavily-loaded truck, with slower acceleration? Or is the vehicle 'dumb' (maybe it's an older car with no communication abilities)? Approaching cars would leave a greater gap ahead of them, switch lanes, etc. Even without giving control over to a central traffic system, we'd see significant improvements in traffic flow. The other challenge for highly-centralized control is the sheer amount of data that's collected by autonomous cars. They apparently generate upwards of 25Gb/data an hour[1] from their various sensors. Figuring out what part of that data needs to be kept, normalized, and then sent to a centralized system is going to be tough. And it'll be hell on the wireless spectrum. Of course, that's assuming V2V spectrum isn't carved up and used for internet access.[2] In which case, things will get...trickier. 0. https://www.mercedes-benz.com/en/mercedes-benz/innovation/car-to-x-communication/ https://www.mercedes-benz.com/en/mercedes-benz/innovation/ca... 1. https://hackernoon.com/automated-cars-and-data-786dfb1e3eb4 https://hackernoon.com/automated-cars-and-data-786dfb1e3eb4 2. http://www.latimes.com/business/autos/la-fi-hy-talking-cars-20160825-snap-story.html http://www.latimes.com/business/autos/la-fi-hy-talking-cars-...