Our understanding is that a one way buffered bike lane will be installed in both Spruce and Pine Streets along most of their lengths, made possible by the dropping of a travel lane. Clearly, when implemented, it will be the most significant bicycle friendly improvement in busy Center City since the opening of Schuylkill River Park Trail and street level crossings in 2003. It will also be the City's first (but we hope for additional ones north of Market St.) "river to river and east-west connector" set of bicycle friendly streets.
The reduction of travel (for motor vehicles) lanes may be a concern to some, however more road space does not necessarily mean smoother traffic flow. Delivery vehicles, utility trucks and double parkers already cause Spruce and Pine to function as weaving single lane streets. A great example of less is more would be the closing of Broadway in Manhattan, which actually improved north south traffic flow by eliminating Broadway's angled cross street interference.

6 foot bike lanes with 2 foot buffers on Spruce and Pine Streets will finally make the concept of a Center City bikeway a reality.
The project, overseen by the Mayor's Office of Transportation and carried out by the Streets Department, will be a simple and inexpensive line painting operation; construction could begin as soon as August. Over the next 9 months or so the streets will be evaluated, and if the lanes are proven to be beneficial, then permanent striping will be added when the streets are repaved in 2010.
Read more about this in Sandy Bauer's piece in 07/15/09 edition of Inquirer