What does that mean?
Most superficially, all of the zoning designations in the city have changed. R-10a is now RSA-5, C-2 is now CMX-2, and so forth.
But there are other important changes. The biggest of these is that the Zoning Code is now contextual.
What does that mean? Think of it as a compromise between Euclidean and form-based zoning--while the theoretical structure of the code is still Euclidean, the contextual zoning means that form-based elements are taken into consideration. RSA-5 is essentially each of the three or four different rowhouse designations under the old code mixed into a new designation; the contextual element means that new construction will ideally match existing construction elsewhere on the block (i.e. have the same setbacks, etc.). But large deviations from the norm trigger design review and (probably) rejection.
In short, the code still doesn't allow you to build a commercial addition to your residential property by right (unless your neighbors already have such additions), which is a shame, largely because while it is much less rigidly Euclidean than the old code, it still doesn't allow for the flexibility of use a fully form-based code would.
On the flip side, the new code has made densifying existing commercial corridors significantly easier. CMX-2.5, now the standard on most commercial corridors, allows for mixed-use development up to 55 feet high. 55 feet is by no means an arbitrary number: most major Philadelphia streets are either 50 or 60 feet wide, which means that CMX-2.5, when applied to its utmost, allows commercial streets to achieve a 1:1 street width-building height ratio*.
This does not bode well for midcentury commercial areas, largely because the Philadelphia variant of googie favored single-story commercial structures--essentially, strip malls even if they fronted the sidewalk. We need to undertake documentation efforts, and ensure that an outstanding handful are preserved--primarily in communities where supply and demand are already well-balanced--as well as individual examples that are exemplars of the style (such as Stein Florist at Frankford and Princeton). In this way we can retain a record of the appearance of the built environment without impeding redevelopment and densification of our commercial cores where they are most needed (e.g. along Frankford and Castor).
While the code ensures Center City can be denser and more of a skyscraper canyon than ever before with "Super" CMX-5**, it still underzones other important commercial nodes, leaving them at CMX-2.5 where a FAR-based zoning would be more appropriate. Chelten, Front and Girard, 52nd St., and Bridge-Pratt are exemplars of this issue; all are (or were) crucial commercial centers; all should (probably) be bumped up to CMX-4 (500 FAR, or five stories by right); the main difference is the lack of height limit on the latter. Germantown and Chelten is an example of a cluster of taller buildings that such an upzoning would allow emulation of. Likewise, first steps are being made towards TOD identification and implementation (although that is something that needs to be hashed out in the neighborhood plans).
With parking requirements (one of the more insidious auto subsidies), the Code, again, shows steps towards more current understandings of the role, but not a willingness to fully embrace current understanding. Rowhome parking requirements have been cut out entirely, but larger residential structures still require them, and base commercial requirements have not been changed at all (still at one spot, i.e. 250 ft2, per 1000 ft2 of commercial space). On the flipside, TOD, car sharing, bike sharing, etc., bonuses quickly, and drastically, reduce them or chop them out entirely. Good for Center City, bad for the Northeast.
...Some initial impressions on the new Zoning Code.
* Or 2:1 on Frankford and Castor Avenues in the Northeast.
** "Super" CMX-2.5 has a base FAR of 1600. For comparison, the Empire State Building has a FAR of almost exactly 3300, or double that.