Eric Jaffe discusses the slow transformation of Tysons Corner, Virgina from car-dominated edge city to walkable city:

Last week marked the Silver Line’s first birthday, and with so much riding on it, so to speak, attention naturally turned to the lower-than-expected ridership numbers. The Washington Post reported that the Silver Line is serving about 17,000 daily riders during the work week, well off the pace of 25,000 riders that planners had set by this time. The “bulk” of this ridership aren’t even new users, according to the Post, but rather people who used to take the Orange Line instead…

But while it’s far, far too soon to declare the great Tysons shift a failure, it’s not too early to point out some of the little failings that still need to be addressed.

Poor walkability is one. Citing an internal analysis, Martin Di Caro at WAMU reports that Metro officials believe a lack of “sidewalks, crosswalks, and bike lanes” is a key reason behind the low ridership numbers…

But the neuroscience of driving habits clearly shows that mode choice is most susceptible to change in the early stages of a major life event, such as moving homes or starting a new job. Insofar as Tysons developers have been slow out of the gate when it comes to encouraging transit, walking, and biking, they might be missing a critical opportunity to change commuter behavior…

A third setback might fall more on Metro itself. The Post’s Dr. Gridlock reports that the biggest problem facing Silver Line ridership isn’t the stations—it’s the service. A delay on new rail cars forced Metro to stretch the existing fleet thin. The proposed fix involves running fewer eight-car trains during rush-hour twice a week so the older cars can get maintenance; given the strong ties between transit service and transit ridership, that’s not an encouraging proposition.

Transforming an exemplar of suburban sprawl is not easy: the community has to respond with corresponding infrastructure (improving walkability), changed mindsets (getting people into new patterns and perhaps this requires newer residents), and adequate service to make it viable alternative.

However, we might ask how much time is needed before we could properly evaluate the impact of the Silver Line. Five years? Twenty years? A couple of generations? And it matters who is doing the evaluating and for what reasons. Is this about seeing a financial impact (paying for the construction of the new line plus measuring new development prompted by the new line)? Assessing the decisions of politicians? Trying to reach a magic number of daily users? It will be interesting to watch the ongoing analysis and who gets to take the credit or blame.