Posts from — December 2008

Parts 1 and 2 of this series looked at the public side of the DC Alternatives Analysis process that took place between 2002 and 2005. Several newsletters were published, public meetings were held, and the study team met with civic groups and maintained a presence at various community events. The widely distributed documents only tell a small fraction of the story, and if one wants to understand why the final report had such disappointing recommendations, one needs to delve into the more technical study documents, which weren’t widely distributed. The contrast between that which was published publicly and the technical documents kept internally is instructive for anyone following a similar engineering study of similar scale.

Broadly speaking, these technical documents attempt to quantify the decision-making process in order that every subsequent decision have justification. The process obscures the study biases by shifting them into the methods of quantification, and ultimately confuses quantifiability with importance.

Setting the Stage

The formal program of the study was documented in the Project Work Plan, in January 2003. One of the first of the study documents was the short Quality Assurance Program, an eight-pager released in November 2003. It establishes the tedious tone in which all further study documents will be written with empty management-speak such as “All DMJM Harris staff performing tasks on the project will utilize the appropriate implementing procedure for the work being performed.”

Two reports were finished in August 2004: The Needs Assessment and the Evaluation Framework. These followed the extensive series of community meetings in late 2003. The Needs Assessment was the only technical document that was published on the (now-defunct) study website. It examined population, employment, and overall destination patterns across the city in relation to existing transit service. The Evaluation Framework brought together all the input–from DC agencies and from the community–about routes and goals and needs and defines what sort of analysis is to be done. A structure of seven routes is proposed, two of which have alternative routings, but the stops along those routes are not defined yet. The project goals are laid out, and the measures and criteria used to evaluate choices in terms of those goals are defined. The general work plan for several documents that follow is laid out.

Route and Mode evaluation:

Screen 1, released September 2004, evaluates seven potential transit modes (streetcars, “bus rapid transit,” light rail transit, diesel multiple units, automated guideway transit, monorail, and heavy rail), and ends up recommending only streetcars and “bus rapid transit” for further evaluation.

The Definition of Alternatives, released in November 2004, analyzed the routes given in the Evaluation Framework for the two chosen modes. Station locations were assigned and propulsion technologies are considered. For each route, a “service plan” was developed, including the headways between successive runs and calculations for route travel times. Although there are separate calculations for streetcars and for “bus rapid transit,” no details are given about the assumptions that went into the calculation of the travel times.

Screen 2, released March 2005, takes the service plans and route structure from the Definition of Alternatives and tries to evaluate how well each would fulfill the project goals by applying a set of “Measures of Effectiveness,” which are defined in the Evaluation Framework. Claiming that “the operational characteristics of BRT and Streetcar are similar at the level of detail” under study, it lumps both into a “premium transit service option” to decide whether a particular corridor should have “premium transit,” or whether it should only receive some bus service enhancements. Corridors were ranked (high, medium or low) based on a few criteria for each of the four project goals, leading to a composite score. Further analysis on meeting corridor deficiencies and operational considerations, and concluded by recommending some routes for “premium transit” and relegating some to get only “local bus enhancements.”

Screen 3, released May 2005, takes the “premium transit” corridors of Screen 2 and applies further “Measures of Effectiveness” to determine whether each corridor should be Streetcars or  “bus rapid transit.” Each corridor is broken into segements, and the effectiveness criteria are applied to the segments individually. Where applicable–which isn’t as frequently as one might think–Streetcars and “bus rapid transit” are evaluated separately. The scores from these evaluations are totaled, to come up with proposals for streetcar routes, “bus rapid transit” routes, and “rapid bus” routes.

And onwards

Further study documents, released May–September 2005, looked at the finances of the proposed system and put forward the timetable. All the study findings were summarized in a final report, published in October 2005. Future posts in this series will look in detail at some of these technical reports.