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Autonomous vehicles are great for increased speed, improved (i.e. no) parkability issues and lower car accidents. However, like any latency improvement, they wi

Autonomous vehicles are great for increased speed, improved (i.e. no) parkability issues and lower car accidents. However, like any latency improvement, they will not (can not) improve throughput. Trains on the other hand are optimized for throughput and cost. Point: They are complementary technologise, solving fundamentally orthogonal problems, and can and should co-exist to create the best possible infra. (P.S. I already train from CapHill to UDistrict then get an Uber within the UDistrict) That said, you're welcome to argue that Seattle does not and will never need the throughput optimization provided by trains. That cars alone are enough. But I don't believe it's in your best interest, to compare the throughput of cars to trains. Actually it may even be an active disservice to the autonomous car movement to try and compare them to trains (regarding throughput). Meanwhile, anecdotally, living and working on Denny (20 min hilly-walk, 7min bus no traffic): It is consistently bumper to bumper (at all times that matter) and only getting worse. We seem to have a throughput problem! With similar issues on Mercer. If your data is different, I'd love to hear more about that.

forrestthewoods 11y ago
I'm not sure your throughput assertion is correct. As stated in another reply I-5 North congests every single day between the 520 and 45th st exits. Why? Because of a hill. There's a big hill there. And every meatbag driver slows down going up it. Which causes people behind to brake. Which creates a shockwave traffic jam. That wouldn't happen with robot drivers. Nor would cars slow down when they enter a tunnel for reasons I've yet to figure out. Nor would they slow down when exiting that tunnel when their eyes adjust to the summer brightness. Traffic is actually worse on I-90 on bright, sunny days than on overcast (but not rainy) days! Again, that slow down would not happen at all with robot drivers. So I disagree. Autonomous cars can very much improve throughput. The maximum number of cars that can cross a stretch of road at rush hour is significantly higher with autonomous cars than with meatbag drivers. In my opinion. What I really want is Seattle to throw a few million bucks at Google to do a study. Show us a vision of an autonomous Seattle. Build a simulation and present it. If Google gives us a "best case" and we still think light rail is better then great. I'm sold. Let's pick the better option. But right now we're not truly considering all options.
- yazaddaruvala 11y ago
  Like, I said, there are two things: 1. The theoretical throughput limits of cars on highways vs trains, for transporting people, is drastically in the favor of trains. Generally 1 car per 2 secs per lane - 1.5 people per car on average = 3 people per sec on a 4 lane highway. On the other hand a 15mpg train, moves 6m per sec, with a width of 2 meters = 12 m^2 per sec = 12 people comfortably per sec. While this is a relatively slow train, and we are comparing a train (land mass = 1 highway lane) with a 4 lane highway, the math is still drastically in favor of trains. this still holds, even if autonomous cars can achieve a 100% increase to highway throughput limits. 2. Seattle may not need the level of throughput only achievable by trains. You're probably right that currently Seattle does not and will not need more throughput than cars on highways can achieve. However, I don't think this holds true as time continues indefinitely into the future.

forrestthewoods 11y ago

I'm not sure your throughput assertion is correct. As stated in another reply I-5 North congests every single day between the 520 and 45th st exits. Why? Because of a hill. There's a big hill there. And every meatbag driver slows down going up it. Which causes people behind to brake. Which creates a shockwave traffic jam. That wouldn't happen with robot drivers. Nor would cars slow down when they enter a tunnel for reasons I've yet to figure out. Nor would they slow down when exiting that tunnel when their eyes adjust to the summer brightness. Traffic is actually worse on I-90 on bright, sunny days than on overcast (but not rainy) days! Again, that slow down would not happen at all with robot drivers. So I disagree. Autonomous cars can very much improve throughput. The maximum number of cars that can cross a stretch of road at rush hour is significantly higher with autonomous cars than with meatbag drivers. In my opinion. What I really want is Seattle to throw a few million bucks at Google to do a study. Show us a vision of an autonomous Seattle. Build a simulation and present it. If Google gives us a "best case" and we still think light rail is better then great. I'm sold. Let's pick the better option. But right now we're not truly considering all options.

yazaddaruvala 11y ago
Like, I said, there are two things: 1. The theoretical throughput limits of cars on highways vs trains, for transporting people, is drastically in the favor of trains. Generally 1 car per 2 secs per lane - 1.5 people per car on average = 3 people per sec on a 4 lane highway. On the other hand a 15mpg train, moves 6m per sec, with a width of 2 meters = 12 m^2 per sec = 12 people comfortably per sec. While this is a relatively slow train, and we are comparing a train (land mass = 1 highway lane) with a 4 lane highway, the math is still drastically in favor of trains. this still holds, even if autonomous cars can achieve a 100% increase to highway throughput limits. 2. Seattle may not need the level of throughput only achievable by trains. You're probably right that currently Seattle does not and will not need more throughput than cars on highways can achieve. However, I don't think this holds true as time continues indefinitely into the future.