4 ms·

The problem I’ve faced is that the official live update arrival times are often wrong. I’ve fantasized for years about engineering a network of self contained

The problem I’ve faced is that the official live update arrival times are often wrong. I’ve fantasized for years about engineering a network of self contained + solar powered microcontroller / camera units that I could place on top of bus stops to track them myself. Then again, by the time I get around to it the official arrival times will likely have become more reliable. Any rate, great write up- thanks for sharing!

acomjean 4y ago
It’s a fun problem. We hire 4 trolleys for our open studio event in Somerville. One of our volunteers bought some smart phones, and we pulled a together a php and MySQL back end, some google maps and Trolley Tracker. We can see them bunch up over the course of a day. A lot of transportation services have tracking now.
RektBoy 4y ago
Why is the live data wrong? Why is it called live data, then? HH For example, here in Prague, trams always arrives on time schedule or few minutes after that. (you can wait 2minutes lol) Also all of our public transport has publicly accessible GPS tracking. Buses are more off of the time schedule, but you can check the GPS and compute the live time. And subway doesn't make sense to track, since it arrives every few minutes at any station.
- jpribyl 4y ago
  Ha! I should have specified, I’m in the US- I think it’s a large number of factors that ultimately boil down to “there’s no incentive to be accurate” our buses are often 15-30 minutes late. I don’t think this is very typical, but I have even had a bus driver stop mid route, say “this is as far as I’m going today”, kick everybody off, and drive away
samstave 4y ago
Ha! me and several engineers from Lockheed built just such a thin in 2007 -- but we couldnt get funding for it (we built the RFID tracking system for the military) but we were too early for the market at the time and people werent educated about tracking so we go rejected all over....(it was for fleet operations - we built the tracking systems for all weapons shipments and containers for the military at the time.
- jpribyl 4y ago
  This sounds epic! How did you handle powering the devices at night / rainy days? A battery presumably.. but seems like that would seriously up the maintenance cost. You would have to replace the batteries fairly regularly and I have a feeling that without funding anything I cowboy rig would be super flaky. 2007 means that the network would probably have been an issue as well. Though, I’m less worried about that these days.
  - samstave 4y ago
    The network problem was an issue in 2007 - and so we were working with cell companies to get sim cards and a deal - but that was really difficult because cell plans were still super expensive and this was a novel startup. There are two types of RFID [active|passive] active required a battery which was rather small but the pings were so low power that the battery lasts a really long time. We pivoted and built a tracking system for the cannabis industry - but cannabis growers didnt want to pay for anything they werent legally mandated to do so - we built a system called GreenScale which could track all employees in your growfields, bins etc... but again we are a bunch of engineers (my partner designs and builds the crazy sensors for TDK currently but designed the sensors for Google's RF hand sensors) However, currently, we have a medical tracking system we have built for elderly care which integrates with Alexa and will tell you where your elderly care person is, if they accessed the restroom, if they fell... etc - but its based on a custom Ras PI basically and it uses RF as opposed to video etc with highly sensitive pressure sensors and other metrics to determine human action in a room.... When I was Director of OPs for Cognitive networks we buil spying bullshit on every single Vizio (and a couple other brands) TVs and could get a screenshot from any single TV connected to the internet... We were always 5 years too early with our designs... and then all sorts of companies got founded upon things we were already doing 5 years prior... but people didnt undersrtand wtf we were trying to do and we are nerdy engineers and not salesmen so had a shitty time trying to get people to see our visions... One of my partners now in eng manager at netflix instead.
mikepurvis 4y ago
The Transit App [1] crowdsources position data for vehicles. It's a gamified thing that rewards you with points or whatever for leaving the app running with your GPS on while in motion. This lets them have up-to-the-second knowledge similar to how Google Maps running on phones gives Google live traffic data around the world. [1]: https://transitapp.com/ https://transitapp.com/
- j0yb0y 4y ago
  They also recently released a developer API [1]. The free access looks okay for personal use, I haven’t tried it yet. Oh and if your public transit service has GTFS then just install home assistant and get maps and arrival times. [1]: https://transitapp.com/apis https://transitapp.com/apis
  - mikepurvis 4y ago
    True, but I think part of the point is that the GTFS data is subject to the technical competency of your local transit agency, and that seems to vary widely— sometimes they lie about where vehicles are, or pretend that schedule-inferred positions are GPS positions, or they're missing vehicles, or the data is delayed, or whatever. When Transit captures this information from their own users, it's much more trustable— basically all they'd have to watch for is someone maliciously poisoning the data by telling the app they're on a bus when they're really in a car, but that would be a lot of effort to go to just to be a jerk and end up shadowbanned.
l72 4y ago
Arrival time estimates are really difficult. I much prefer being able to see where the vehicle is on a map and make my own decisions, based upon my own experiences. However, I played around with one provider (Availtec's) estimations for Birmingham, AL's bus system. This looked at the GPS position of the vehicle to see when they actually arrived at a stop and back compared it to the running estimation time. As we can see, it isn't great. https://blog.line72.net/2019/08/06/validating-availtecs-bus-arrival-estimates/ https://blog.line72.net/2019/08/06/validating-availtecs-bus-...
srmarm 4y ago
In London? They're usually quite accurate - used to be tracked by roadside beacons so had less resolution but now it's all GPS I think. Of course sudden traffic, letting an elderly passenger get etc will mean that the countdown won't be the same to the second. But that's going to be the same if you used roadside cameras too. Generally it should be seen as more of an estimate based on how long the last bus took to arrive from the same point rather than an exact prediction but it's usually useably accurate in my experience.
- fersarr 4y ago
  Yea so far they are mostly accurate but there have been one or two occasiones with minor delays. I didn't know they used to have roadside beacons :| How did those work?
nsteel 4y ago
In London the TfL API includes access to their live CCTV traffic cameras. I think you now have to register but it should still be there.
- fersarr 4y ago
  really? you can actually see the feed from all the cameras? Oh is it cameras that just show trains?

acomjean 4y ago

It’s a fun problem. We hire 4 trolleys for our open studio event in Somerville. One of our volunteers bought some smart phones, and we pulled a together a php and MySQL back end, some google maps and Trolley Tracker. We can see them bunch up over the course of a day. A lot of transportation services have tracking now.

RektBoy 4y ago

Why is the live data wrong? Why is it called live data, then? HH For example, here in Prague, trams always arrives on time schedule or few minutes after that. (you can wait 2minutes lol) Also all of our public transport has publicly accessible GPS tracking. Buses are more off of the time schedule, but you can check the GPS and compute the live time. And subway doesn't make sense to track, since it arrives every few minutes at any station.

jpribyl 4y ago
Ha! I should have specified, I’m in the US- I think it’s a large number of factors that ultimately boil down to “there’s no incentive to be accurate” our buses are often 15-30 minutes late. I don’t think this is very typical, but I have even had a bus driver stop mid route, say “this is as far as I’m going today”, kick everybody off, and drive away

samstave 4y ago

Ha! me and several engineers from Lockheed built just such a thin in 2007 -- but we couldnt get funding for it (we built the RFID tracking system for the military) but we were too early for the market at the time and people werent educated about tracking so we go rejected all over....(it was for fleet operations - we built the tracking systems for all weapons shipments and containers for the military at the time.

jpribyl 4y ago
This sounds epic! How did you handle powering the devices at night / rainy days? A battery presumably.. but seems like that would seriously up the maintenance cost. You would have to replace the batteries fairly regularly and I have a feeling that without funding anything I cowboy rig would be super flaky. 2007 means that the network would probably have been an issue as well. Though, I’m less worried about that these days.
- samstave 4y ago
  The network problem was an issue in 2007 - and so we were working with cell companies to get sim cards and a deal - but that was really difficult because cell plans were still super expensive and this was a novel startup. There are two types of RFID [active|passive] active required a battery which was rather small but the pings were so low power that the battery lasts a really long time. We pivoted and built a tracking system for the cannabis industry - but cannabis growers didnt want to pay for anything they werent legally mandated to do so - we built a system called GreenScale which could track all employees in your growfields, bins etc... but again we are a bunch of engineers (my partner designs and builds the crazy sensors for TDK currently but designed the sensors for Google's RF hand sensors) However, currently, we have a medical tracking system we have built for elderly care which integrates with Alexa and will tell you where your elderly care person is, if they accessed the restroom, if they fell... etc - but its based on a custom Ras PI basically and it uses RF as opposed to video etc with highly sensitive pressure sensors and other metrics to determine human action in a room.... When I was Director of OPs for Cognitive networks we buil spying bullshit on every single Vizio (and a couple other brands) TVs and could get a screenshot from any single TV connected to the internet... We were always 5 years too early with our designs... and then all sorts of companies got founded upon things we were already doing 5 years prior... but people didnt undersrtand wtf we were trying to do and we are nerdy engineers and not salesmen so had a shitty time trying to get people to see our visions... One of my partners now in eng manager at netflix instead.

mikepurvis 4y ago

The Transit App [1] crowdsources position data for vehicles. It's a gamified thing that rewards you with points or whatever for leaving the app running with your GPS on while in motion. This lets them have up-to-the-second knowledge similar to how Google Maps running on phones gives Google live traffic data around the world. [1]: https://transitapp.com/ https://transitapp.com/

j0yb0y 4y ago
They also recently released a developer API [1]. The free access looks okay for personal use, I haven’t tried it yet. Oh and if your public transit service has GTFS then just install home assistant and get maps and arrival times. [1]: https://transitapp.com/apis https://transitapp.com/apis
- mikepurvis 4y ago
  True, but I think part of the point is that the GTFS data is subject to the technical competency of your local transit agency, and that seems to vary widely— sometimes they lie about where vehicles are, or pretend that schedule-inferred positions are GPS positions, or they're missing vehicles, or the data is delayed, or whatever. When Transit captures this information from their own users, it's much more trustable— basically all they'd have to watch for is someone maliciously poisoning the data by telling the app they're on a bus when they're really in a car, but that would be a lot of effort to go to just to be a jerk and end up shadowbanned.

l72 4y ago

Arrival time estimates are really difficult. I much prefer being able to see where the vehicle is on a map and make my own decisions, based upon my own experiences. However, I played around with one provider (Availtec's) estimations for Birmingham, AL's bus system. This looked at the GPS position of the vehicle to see when they actually arrived at a stop and back compared it to the running estimation time. As we can see, it isn't great. https://blog.line72.net/2019/08/06/validating-availtecs-bus-arrival-estimates/ https://blog.line72.net/2019/08/06/validating-availtecs-bus-...

srmarm 4y ago

In London? They're usually quite accurate - used to be tracked by roadside beacons so had less resolution but now it's all GPS I think. Of course sudden traffic, letting an elderly passenger get etc will mean that the countdown won't be the same to the second. But that's going to be the same if you used roadside cameras too. Generally it should be seen as more of an estimate based on how long the last bus took to arrive from the same point rather than an exact prediction but it's usually useably accurate in my experience.

fersarr 4y ago
Yea so far they are mostly accurate but there have been one or two occasiones with minor delays. I didn't know they used to have roadside beacons :| How did those work?

nsteel 4y ago

In London the TfL API includes access to their live CCTV traffic cameras. I think you now have to register but it should still be there.

fersarr 4y ago
really? you can actually see the feed from all the cameras? Oh is it cameras that just show trains?