A while ago, the Pittsburgh Post-Gazette asked several different people what they think should be done to improve traffic between Oakland and Downtown. SeePittsburgh Post-Gazette - Benchmarks. Apparently, an idea that was abandoned in 1996 was to have the Downtown "T" system connected to Oakland, either by an underground light rail line acting as a subway, or as an above ground line. The cost for this expansion that was floated around was around 1$ billion dollars. My guess is that this cost was for an underground line and that it was likely to be much less if it took an above ground route.
Anyway, let's think about this idea logically. Oakland is one of the biggest employment areas in the entire state. The downtown to Oakland corridor is one of the most heavily traveled corridors in the state as well. But lets think about the people who are making that trip...
Two obvious groups come to mind: students and workers. The students making that trip are going downtown for various reasons. However, from my experience as a student at the University of Pittsburgh Law School is that the only students who went downtown for any reason at all was to go to jobs in downtown firms. No one went downtown for any other reason. If people needed to go downtown, they typically would drive instead of taking the buses.
Ah, the buses! That's the current method of getting from Oakland to downtown on mass-transit. The heavily traveled "Fifth and Forbes" corridor takes buses down both of those streets in both downtown and Oakland. This is the spine of the "spine line" idea. The trip doesn't take that long. Additionally, the trip in reverse (downtown to Oakland) has the additional advantage of continuing onwards to points east of Oakland. Oakland is a major stop on the way for most of these buses, conveniently located between downtown and points east. Thus, there is a pretty good bus system already in place between downtown and points east.
That brings us to employment. Workers are the main people who use the "T" system as it is. Workers would probably be the primary ones to use the "T" system east of downtown. So, people who live in Oakland could take the T into downtown. Alternatively, they could take the already existing bus system into downtown. Additionally, the "T" system wouldn't be much of a benefit to Shadyside. Shadyside already has a direct route into downtown via the east busway. In fact, so does East Liberty, Homewood, Wilkinsburg, Edgewood, Swissvale and Rankin. All of these are points east of Oakland and Squirrel Hill which are served by the "T". Additionally, the EBO route serves the busway and connects directly into Oakland itself. Thus, Oakland is already connected to those commuters in "points east". Commuters in "points east" are connected to both Oakland and downtown via the east busway.
Because these commuters are already serviced by the east busway, you have to think that an extension past Oakland could service Squirrel Hill and ... well, and not much else. It could turn south maybe and head towards Homestead and the Waterfront development down that way. However, if the primary focuses is commuters into Oakland and downtown, serving a shopping area doesn't meet that goal.
Thus, an evaluation of the spine line extension of the T system must focus on servicing Oakland and Squirrel Hill. Could these two places use a T system? Maybe. Are these two places adequately serviced by buses? I'd have to say yes. The Oakland area is serviced by bus routes 100, 28K, 28X, 44U, 500, 501, 53F, 53H, 54C, 56U, 59U, 61A, 61B, 61C, 67A, 67C, 67E, 67F, 67H, 67J, 69A, 71A, 71C, 71D, 74B, 77U, 81A, 81B, 84A, 84B, EBO. That's 31 bus routes serving the area. Many of the bus routes (those with a U designation, are direct routes to Oakland and don't go downtown. Many of them do go downtown (the 61s, the 71s, the 67s). Squirrel Hill is serviced by 501, 56U, 59U, 61A, 61B, 61C, 64A, 67H, 69A, 74A, W, with the first 5 routes travelling directly from the universities to the heart of Squirrel Hill. 67H is a direct route from Squirrel Hill to downtown. 64A and 74A service other areas then Oakland and downtown.
My point being is that at present, there are many opportunities to commute by bus from both Squirrel Hill and Oakland. Commuters aren't going to want to walk the extra distance to the Squirrel Hill T station if they can just walk to the corner to take the bus. Thus, unless there are drastic cut-backs in the number of bus lines which service either Squirrel Hill or Oakland, people are going to go for what is convenient to them.
In the end, if it were built, I think it will end up to be the unfortunate case of an expensive system being built to service a rather small number of people. Any projected estimates are likely to be off by many many people per day. Alas, this is the norm for projects in the southwestern Pennsylvania area. Other examples include the recently opened Wabash Tunnel, the HOV lane north of the city, the Beaver Valley Expressway, the Greensburg Bypass, and the Mon-Fayette Expressway, not to mention the famous "Bridge to Nowhere" which is now the Ft. Duquesne Bridge.
Building an extension of the T system to Oakland and beyond would end up being a waste of money. A giant project that politicians can point to with pride...until the actual ridership numbers come in. Then, they'll find someone else to blame; they'll blame us, the citizens for not riding the public transit system.
After all, when was the last time you saw the mayor of Pittsburgh on the bus?