The New York Times recently reported on the success of the Phoenix light-rail line exceeding its forecast ridership. Of course, it's telling that the fact the light-rail line exceeded its forecast is newsworthy. Most don't. In fact, it's now considered a "success" if actual ridership falls 20% short of the forecasts used to justify the investment.
A Federal Transit Administration report published in 2007 titled "Contractor Performance Assessment" tracked 19 fixed guideway (mostly rail) transit projects. Based on ridership forecasts from the initial planning documents (Alternatives Analysis), just three (the San Diego El Cajun line, the St. Louis Initial system, and St. Louis Clair Extension) exceeded their forecasted ridership. Three others were within 20 percent of their forecasted ridership: BART Colma line, Denver's SW light rail, and the Salt Lake City south light rail line.
Notably, the FTA report lauds the improvement in the forecasts, even though systemic biases in over estimating ridership are clear:
"Overall, almost 60 percent of the projects studied [in the FTA report] can be expected to achieve at least two-thirds of their forecast ridership by their forecast year. Comparing these results to the projects analyzed in the [earlier] 1990 study reveals that more than half of ridership forecasts for the recent projects performed better than the best forecast of the older study."
In other words, the record of forecasted ridership is still dismal--few, if any are even expected to meet their original ridership forecasts. The benchmark, in fact, appears to be whether these forecasts are within 20 percent (on fifth) of the forecast used to justify a public commitment to the project. (So, as a rule of thumb, take projected ridership and discount it by 20 percent for new projects.)
But, still, give Phoenix it's due. Average weekday boardings are running at 33,000, higher than the forecast of 26,000. Unfortunately, a few cautionary flags are evident in the actual ridership numbers. According to the New York Times:
"The light rail here, which opened in December, has been a greater success than its proponents thought it would be, but not quite the way they envisioned. Unlike the rest of the country’s public transportation systems, which are used principally by commuters, the 20 miles of light rail here stretching from central Phoenix to Mesa and Tempe is used largely by people going to restaurants, bars, ball games and cultural events downtown.
"The rail was projected to attract 26,000 riders per day, but the number is closer to 33,000, boosted in large part by weekend riders. Only 27 percent use the train for work, according to its operator, compared with 60 percent of other public transit users on average nationwide."
This should be troubling for light-rail supporters. Fixed guideway transit works best when it moves people from one high density place to another. That's why they tend to work better on hub-and-spoke transportation systems that key in around a downtown or Central Business District. With such a low commuter share of travel, Phoenex's light rail system doesn't appear to be competitive with its more important travel market: downtown commuters.