Content Management
One of the biggest challenges for 415 was to create a flexible and extensible CMS. They did this by putting much of the functionality in generic JScript modules, which weren't specific to the task at hand. This had the added advantage of making the code reusable in other projects. In addition, they separated the display engine cleanly from the CMS.
The underlying database structure also had to be extensible. Even though it was based on previous work, the database design was a lengthy process, taking about a month. The team attributes much of the project's success in their care in perfecting the crucial database infrastructure.
Doing that required a lot of communication between 415 and BART. Because so many people were involved on both sides, there was a tremendous potential for confusion and crosstalk. The companies addressed this problem by limiting cross-team communication to 415 producer Leslie Bamburg and Moore, a rule that Moore says made the whole process move much more smoothly.
Accessibility
BART paid a lot of attention to accessibility considerations when developing the site. For instance, it included a text-only site for people whose computers couldn't handle graphics. The CMS publishes the graphical and text versions of the site simultaneously.
The text-based site conforms to the highest accessibility level (Triple-A) of version 1.0 Web content accessibility guidelines published by the W3C (www.w3.org/TR/WAI-WEBCONTENT/wai-pageauth.html). Even the graphics-based side conforms to the lowest W3C accessibility level (A).
Another aspect of accessibility was cultural accessibility, namely, making at least a limited amount of information available in several languages other than English—including French, German, Spanish, Italian, Japanese, and both traditional and simplified Chinese.
Palm App
BART also wanted to enhance accessibility by providing access to scheduling information via various types of devices. BART commissioned Oakland, CA Web and mobile developer Bear River Associates (www.bearriver.com) to create a scheduling application that users can download to a Palm PDA.
The biggest challenge in creating the Palm application was compressing the data to run on the low-powered Palm device. In the server application, the scheduling database is about 2MB. Bear River managed to reduce that to about 16KB.
"There was a lot of regularity to the data," explains Bear River Senior Consulting Engineer Jim Morris. For instance, trains typically run at regular intervals, perhaps with one interval for peak and one for off-peak hours. Just as with ordinary file compression, more repetition means more potential for compression. The special rules for bicycles created a modest challenge. In addition, BART's grand meet policy—which says that you should be able to take the last train out of any station and arrive anywhere in the system—proved "interesting" from an algorithmic perspective, says Morris.
Reducing the database to 16KB meant Bear River could implement the entire application, including the executable, the database, and a bitmap of the BART system, in under 160KB. Zipped, even including 20K of user manual and license agreement, it's just a 75KB download. The development was done in C++, using Bear River's open source framework for the Palm, "paf" (www.bearriver.com/developer/palm).
Bear River also created some utilities for people who manage scheduling at BART, to make it easy for them to update schedules.
The whole development process lasted about twelve weeks with two people working on it, Morris and Senior Consulting Engineer Alan Clute.
Hardware
All of these new features meant a system overhaul as well. Today, the site is hosted on two Dell PowerEdge 2450 Web servers running Microsoft Windows NT 4.0 and IIS, and two Dell PowerEdge 2450 database servers running Microsoft Windows NT 4.0 and SQL Server. Each server has two 866MHz Pentium III processors, two 10GB hard drives in a RAID 5 configuration, and 1GB of RAM. A fifth server is dedicated to log storage and analysis.
