Tuesday, April 17, 2018

Spontaneous Accessibility for Event Response

On March 16, two escalator outages essentially knocked out access to a significant node in Seattle's transit network. In a post on Seattle Transit Blog's community blog, I discussed how Spontaneous Accessibility can be used to assign a monetary cost to such an event. Any mitigation or preventative measure is going to have a cost; how can the right one be chosen unless the cost of the precipitating event is known as well?

Monday, February 26, 2018

Catching Up

Though it's been several months since the last post on the blog, work on Spontaneous Accessibility measurement has been anything but stagnant. Here are the highlights:
  • Measuring Spontaneous Accessibility for Iterative Transit Planning, a paper covering, in greater formality, many of the topics discussed on the blog, was accepted for presentation and publication by the National Academies of Sciences, Engineering, and Medicine's Transportation Research Board (TRB). It also was selected by the TRB's Committee on Transit Capacity and Quality of Service as the best paper that the committee reviewed in 2018. Presentation occurred at the Transportation Research Board Annual Meeting in January and the paper will be published later this year in the Transportation Research Record.
  • The ScoreGenerator software has received many updates. Most important have been changes to ensure the generation of consistent Spontaneous Accessibility measurements for the same data. The previous inconsistencies were small: typically a single-digit amount in several million opportunities. Eliminating them ensures that when the ScoreGenerator is used comparatively, it measures the changes to the network, and only those changes.
  • Spontaneous Accessibility analyses on cities other than Seattle are underway.
  • I have started experimentation with a configuration language for describing modifications to transit networks. This simple and precise language opens up the possibility for rapid testing of hypothetical network changes.
With the paper written and the software enhancements in place, I'm looking forward to running new Spontaneous Accessibility experiments, and of course, blogging about them here.