Not as catchy as the Bike Rack Rap, or as flashy as the cool bus. But a lot more relevant.
Category: Uncategorized
Background Nerd Reading: on Location
I’ve come across a few good resources on GNSS which are worth sharing (because calling satellite positioning systems ‘GPS’ is so 2005).
The first is on measuring the accuracy of position information from a positioning system. I’ve always understood accuracy of positions to be probabilistic, i.e. a certain percentage of the time, the measurement will be within a certain distance of the ‘true’ value. That distance grows with the desire to be more confident about the measurement. How is that expressed constantly? Enter CEP, DRMS, 2DRMS, and R95. They are explained here (with a bit of spunk) and here (with some more math).
Finally, the EU in one of it’s many framework programs, has put out a white paper on the current and emerging state of GNSS technology. Like any good EU Framework project, it has an acronym: SaPPART, or Satellite Positioning Performance Assessment for Road Transport. It’s a great read, if you’re in to this sort of thing. And if you’ve read this far, you probably are.
YAWTPGTFS– Yet Another Way to Plot GTFS
Transit-awesome!
Transit awesome is a crowdsourced list of “awesome” (many free and/or open-source) technology projects for transit. If this blog ever had a links page, this already has everything on it.
Interesting Slides on APIs
Below the fold is an interesting presentation from Tim Moore of BART on their API usage.
Background Nerd Reading: Transport Modelling for Beginners
This post is the introduction to a series of posts on transport modelling (he’s using the Queen’s English, note the use of “bus pairing” over the American “bus bunching”). It is well worth a look, especially for the acknowledgements of the trade-offs in modelling and planning service.
The goal of this post: To introduce you to the world of theoretical transit modelling, validate the field, and motivate you to listen to what models are able to tell us.
To appreciate this post: In order to follow some of the conclusions presented in this post, an understanding of fairly basic high school math is needed.
TL;DR: I make the case that mathematical models are a misunderstood but valid way of gaining valuable insights about transit with a relatively small amount of investment. I introduce the real-world concept of bus pairing, and go through a 1964 derivation that leads to an equation that describes this phenomenon. I conclude with
Electronic Passenger Information is not new.
Passenger information has been on the mind of the transit industry for over a century! An electronic passenger information sign was installed at at Boston’s Park Street in the 1890s-1900s. At the time, there were numerous (40+?) lines running through the station, and when properly staffed, this would have been pretty helpful.
I have not been able to pin down the exact source of this. I believe it was from one of the Boston Transit Commission annual reports, but I have not found a copy of the exact issue.
Will GTFS-rt move further into the standards realm?
An interesting post on the gtfs-realtime group is worth following.
Beginning to addressing problems that some have with the GTFS/GTFS-rt ‘standards,’ which some sticklers decry as mere de-facto standards, as they don’t follow standards development processes.‘ Developing the GTFS in typical tech industry fashion, these practices were acknowledged, but not closely followed.
This has definitely ushered an explosion of open data and accelerated delivery of countless sucessful applications (unlike other transit data standards). But now that progress is slowing.
The complete original post saved for posterity (because you never know if it’ll be available in the future) is below the fold.
Continue reading “Will GTFS-rt move further into the standards realm?”
Welcome to Transitland
Mapzen’s Transitland is a library/service for aggregating and providing data from GTFS on a multi-agency/multi-region scale. Transitland aims to provide client-level (the ‘faucet’) services. TransitFeeds is a comparable service, but without US-based evangilism.
AC Transit Institutes Service Changes*, Doesn’t Fully Explain Their Magnitude
Update: AC Transit just put out a press release via email making the following clear. My minor scoop only lasted for a day.
Turning the Corner: District Begins to Expand Service
During the worst of the Great Recession, the District went through painful budget cutting and our customers lost service on the street. But over the last several years, the combination of the District’s efforts to reduce costs and operate more efficiently (including purchasing newer buses), the growing economy, and an increasing ridership has enabled us to begin adding service again.
The first round of enhancements total $2.7 million in annual service. Half of these were implemented in December and the remainder will launch on March 15
Among the exciting enhancements are the introduction of weekend service on the San Pablo Rapid from Richmond to downtown Oakland…
Continue reading “AC Transit Institutes Service Changes*, Doesn’t Fully Explain Their Magnitude”