There’s a habit of considering ridership projections as an essentially political document — and with all the arguing, perhaps they are — but at its heart lies a technical model with actual inputs and assumptions. One of those inputs, of course, is previous ridership, when that data exists.
I’m a bit late on this, but now that ST has a full year of Central Link ridership data with Seatac station included, it has another input to its model. As that ridership was lower than expected, it’s caused a general downward revision to ridership going forward. The upshot is that 2011 ridership is projected to average 25,000 weekday boardings, instead of 31,000. There are also revised estimates for Tacoma Link, Sounder, and ST express.
ST spokesman Geoff Patrick tells me that these estimates are the first that use 2010 ridership as an input. They also incorporate the latest economic forecasts; Patrick points out that “there are 30,000 fewer jobs in downtown Seattle today than there were in the year 2000.”
It’s a little odd to me that there’s still supposed to be a big jump in 2011, and then much smaller increases through to 2016, so my (totally amateur) instincts tell me this number is still too high. In any case, models are always wrong, although they do have their uses. In the next few days, we’ll have a more detailed analysis of the ST ridership model and its errors.