Which is the Biggest Number?
Which is the biggest number -- 580,000 or 626,000? The obvious answer is "626,000." But why am I asking what seems to be a stupid question?
The new proposed budget for WMATA states (p.10) that Metrorail reduces 580,000 car trips each day, which, in turn, benefits other commuters who drive. Sounds reasonable to me.
However, an informal study of the many proposed amendments to the Comprehensive Plan for Tysons Corner estimates that, if the Silver Line is constructed and if the Fairfax County BoS approves the Plan amendments, we could expect to see an additional 626,000 car trips each day, in and around Tysons Corner. In other words, adding "density," "transit oriented development," "mixed use," etc. to Tysons Corner would likely put almost 8% more cars on roads in and around Tysons Corner than Metrorail takes off the roads throughout all of Metropolitan Washington, D.C., Virginia and Maryland.
The informal study examined each and every proposed Plan amendment, assumed that the BoS would approve Floor Area Ratios of only 3.0 (three square feet of floor space for every one square foot of lot size), and extrapolated car trip data from the recent Plan amendment for the McLean Commons Apartments. The study then assumed that 20% of these potential car trips would be captured by the Silver Line, leaving an additional 626,000 car trips each day in and around Tysons Corner.
They study is conservative because many of the applications are seeking FARs that are higher than 3.0. It also assumed a "capture rate" that is higher than Gerry Connolly has been touting for the Silver Line. Therefore, we could see even more than 626,000 additional, daily car trips in the Tysons Corner area!
Spending billions to build a new rail line that will trigger rezoning approvals, which in turn will add more traffic to Tysons Corner than the entire Metrorail system takes off the roads today just seems foolish to me.
The new proposed budget for WMATA states (p.10) that Metrorail reduces 580,000 car trips each day, which, in turn, benefits other commuters who drive. Sounds reasonable to me.
However, an informal study of the many proposed amendments to the Comprehensive Plan for Tysons Corner estimates that, if the Silver Line is constructed and if the Fairfax County BoS approves the Plan amendments, we could expect to see an additional 626,000 car trips each day, in and around Tysons Corner. In other words, adding "density," "transit oriented development," "mixed use," etc. to Tysons Corner would likely put almost 8% more cars on roads in and around Tysons Corner than Metrorail takes off the roads throughout all of Metropolitan Washington, D.C., Virginia and Maryland.
The informal study examined each and every proposed Plan amendment, assumed that the BoS would approve Floor Area Ratios of only 3.0 (three square feet of floor space for every one square foot of lot size), and extrapolated car trip data from the recent Plan amendment for the McLean Commons Apartments. The study then assumed that 20% of these potential car trips would be captured by the Silver Line, leaving an additional 626,000 car trips each day in and around Tysons Corner.
They study is conservative because many of the applications are seeking FARs that are higher than 3.0. It also assumed a "capture rate" that is higher than Gerry Connolly has been touting for the Silver Line. Therefore, we could see even more than 626,000 additional, daily car trips in the Tysons Corner area!
Spending billions to build a new rail line that will trigger rezoning approvals, which in turn will add more traffic to Tysons Corner than the entire Metrorail system takes off the roads today just seems foolish to me.
posted by Toomanytaxes at 5:08 PM
2 Comments:
How did they calculate that 580,000 number?
Recent studies sugest that it takes two transit trips to eliminate one car trip. In other words, transit is only 33% efficient at taking cars off the road to begin with.
Not only that, but it is not particularly energy efficient, and carrys a lesser load ratio than cars do.
Sometimes I wonder about us.
Ray,
Good question. I know how the 626,000 figure was estimated because I asked people who worked on the study. I suspect that I could ask WMATA. I'm not sure how quickly I'd receive an answer. The poor agency is understaffed, they say.
We simply need to move debate on transportation beyond the "fact free zone" where it operates today.
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