When calculating Link ridership, Sound Transit staff record the data provided by infrared electric eyes over the doors on some cars. Reading that data is something of an art – the sensors take some tuning and the data isn’t always perfect. It’s not just a “one” or a “zero”, we’re told – children register differently, for instance. Sound Transit controls for all this when calculating ridership – and sends out manual counters to be sure they’re getting accurate numbers.
As a result, though, sometimes ridership numbers are wrong. Sound Transit found two small errors in their counting methods – one for Tukwila station in the summer and one for Airport station (affecting late December data), and in both cases were throwing out good data that looked bad in the first pass.
It turns out (Excel), in fact, that December weekdays averaged just over 14,900 (300 higher than previously reported), with a peak day on December 28th with over 19,950. Weekdays after Airport Link opened were averaging 17,350. I’ve seen anti-transit activists claim as few as 12,000 weekday riders – don’t let them.
With ridership off by 15% in Portland, this looks pretty good. We’ll have to wait to know how far off Metro ridership is, but I’m willing to bet that without a recession, Link would be beating projections.