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mft_ • today at 1:42 PM • 3 replies • view on HN

Regarding public transport route design, I've long wondered how much efficiency current routes in a given country might be leaving on the table.

As in: if one collected sufficient anonymised travel data to offer a reliable understanding of the population's travel needs, and given the fixed constraints of the existing road and rail network, and the existing number of buses and trains, how much more efficient could the network be by varying routes, timings, stops, and interactions?

Imagine if such a dataset was made available, and a prize offered for the best solution.

The challenge could also be extended to explore optimal areas for investment in additional infrastructure - a wider road here, a new roundabout or branch line there.


Replies

abdullahkhalids • today at 2:04 PM

Pretty much all large public transit authorities already collect all sorts of data about requirements and usage, and have scientists/engineers on payroll to optimize the network within the economic and political constraints these systems operate in.

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nickorlow • today at 2:05 PM

due to how hard it is to change the networks, I think there's a lot of inefficient route design. if you look at SEPTA in Philadelphia, they're in the middle of realigning a lot of their bus routes for the first time in 60 yrs and ridership has increased noticeably since they started.

bluGill • today at 2:04 PM

Well, there is some of that. It's not near as much as you might guess. Predictable transit is very helpful because people plan their life around it. What the data you're looking at will show where the bottlenecks are, and yes, you can remove a few bottlenecks and make people's life a little bit better, but it's not going to be a major change because of major change will not show up in the data until well after it's made.

I don't remember the terms used, but I've seen data sets of where people live and work in Manhattan, and you do see people who live on subway lines take jobs on that same line, and they don't take jobs on a different subway line that while possible is overly inconvenient.

people have already arranged their life around the existing transportation that exists around them. They are not going to change their life because it is already in place. They want bottlenecks fixed but otherwise don't really need a change to their life. Even if a change would greatly benefit them, they often can't see that and wouldn't imagine themselves making the change to their comfortable life.

The real value of transportation experts is they can look at a map and all your data and say, if we make these changes, over 20 years, the city will redevelop in this way, and then we can ask questions. "Is that how we want the city to develop?" however, the data is never going to show that because the data shows what people are doing today, not what they're going to do in 20 years. Don't get me wrong, experts get this wrong too when they make predictions. However, there is a lot of things we can use to inform our predictions. even though we're not perfect, we can make predictions that are usually right.

Varying the route timing is the absolute worst thing you can do. People need to depend on your transport system. If they have to look at a schedule that's going to change by day to figure out when they can actually get somewhere, they're going to get frustrated and start looking up for an alternative that they control. If you vary your timing at all, it's only because you're changing between a train every minute to train every five minutes. You don't get to go any farther apart than that without losing writers because they no longer can trust that the system will get them there when they want to be there. Physics puts a lower limit on time. I believe the current record is a train every 90 seconds, and I'm not sure how much closer together you can get. The limit for a bus is three minutes apart and even that is extremely hard.

Transit systems that are running worse than 5 minute frequencies have large drops in ridership and as they increase frequency: ridership jumps because people start to use, they can always just go out when they're ready to go. If this wasn't so expensive, everyone in the world would be running 5-minute frequencies all day.

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