Tuesday, December 17, 2013

Compromises on North Broad

Jon Geeting recently picked up on an implicit idea in my Width, and the Perception of Width article: giving Broad Street the same design standard as e.g. Paris' Ave. Kléber. He has also run further with this idea than I ever conceived, including the idea of putting a BRT lane down Broad. While these are all good ideas in their own right, however, at a certain point Broad Street--especially North Broad--will demand, at a certain level, compromise.

The reason for this is a legacy of highway projects that never got built, particularly in the northern suburbs. While this is, as Alon Levy pointed out, good for mass transit (and a major reason why reactivations of the Newtown Branch and Bethlehem Branch (at least as far as Quakertown) are good ideas), it does impose a certain stark reality on Broad Street.
The 309 (blue) and 611 (red) corridors both feed into North Broad.
Both of the major highways serving the northern suburbs--PA-611 and PA-309--drain onto North Broad. Because of this, much of the traffic into Center City from central Bucks and Montgomery Counties comes down North Broad: while the Northeast Corridor May function as an escape valve, it only serves a small portion of the northwest corner of this area; commuters from Ambler, Doylestown, Flowertown, Glenside, Hatboro, Jenkintown, Warminster, or Willow Grove have little choice other than SEPTA or North Broad. And of course, commuters from (especially) Churchville and Richboro have none. This makes North Broad's demand far higher than South Broad's, one of the reasons why the current traffic pattern involves converting a parking lane into a through lane at peak.

This raises the difficulty that, while an MWB would be easy to implement on South Broad, it is somewhat more difficult on North Broad. While it certainly offers significant traffic calming and safety improvements, it doesn't really address flow interruption congestion (congestion caused by traffic lights), which the peak fifth lane functions as a band-aid for; implementing it as a reversible lane would  (a) make it quite difficult to fit everything else onto the street, in addition to being (b) quite ugly. And of course, the real solution to the flow problem--eliminating traffic lights--would be catastrophic for all other users. All of this implies that North Broad requires, at minimum, four through lanes with good light timing minimizing stops, which, of course, dashes any hope of BRT on the corridor. (Not that the 4 or 16, with the subway underneath, really need it.) That said, BRT would be useful on several other corridors, such as Erie, Allegheny, Lehigh, and Washington Aves. BRT could be run down the less busy South Broad corridor, but it is, if anything, even less useful there (cf. Reading Between the Lines).

So the key is attaining a tradeoff--a balance of priorities. To do this we need some sort of hierarchical modal evaluation criteria. This could be easily abused and turned into a checklist by the same kinds of numbnuts who eviscerated any pretense of urbanism in Syracuse, but having such a checklist exist, and be public knowledge, would be an invaluable tool in project evaluation and project criticism. But what would this entail? To see my answer, partitioned from this post due to increasing lengthiness (not that that's stopped me before) and as subject matter deserving its own post--stay tuned.

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