Another example of ridership not decreasing (or increasing) after a fare increase:

http://www.nytimes.com/2005/05/20/nyregion/20fare.html?

The New York Times
May 20, 2005
Transit Riders Keep Buying 30-Day Cards
By SEWELL CHAN

The 30-day MetroCard became more popular with subway and bus riders in
March, right after its price increased, surprising transit officials who
had thought that demand would slacken, at least temporarily.

Statistics released by New York City Transit yesterday offered the first
glimpse at changes in fare-purchasing patterns since fares went up on Feb.
27.

Unlike previous increases, the February increase affected only the 7-day
and 30-day unlimited-ride fare cards, along with express-bus fares. The
base fare, $2 for a single subway or local bus trip, did not change, nor
did the discount for regular MetroCard purchases of $10 or more.

The price of the 7-day card rose to $24 from $21, or 14.3 percent. The
30-day card rose to $76 from $70, or 8.6 percent.

In March, the 30-day card accounted for 28.1 percent of all fares sold,
the highest proportion recorded since unlimited-ride cards were introduced
in July 1998. A year earlier, the monthly card accounted for 23.6 percent
of sales.

In contrast, the 7-day card accounted for just 22.6 percent of sales in
March, the lowest proportion since June 1999 and a significant drop from
27.5 percent a year earlier.

Fares have become far more complicated in the past decade. The MetroCard
was introduced in January 1994, free transfers between subways and buses
in July 1997, volume discounts in January 1998 and a one-day,
unlimited-ride Fun Pass in January 1999.

Riders face a hodgepodge of calculations in determining which type of fare
card makes the most sense. They must take into account not only their
regular commute, but their likelihood of using a subway or bus on holidays
and weekends.

The transit agency, which is the largest subsidiary of the Metropolitan
Transportation Authority, uses economic models to predict the effects of
fare increases.

The agency predicted that the February increase would result in a shift
away from both the 7-day and 30-day cards and toward the regular cards.
(With the discount, a $10 card is good for six rides, at a cost of $1.67 a
ride.)

Instead, customers appear to have moved away from the 7-day card while the
30-day card has kept its customers and may have attracted some new ones.
It is possible that many riders take the subway so often that the $6
increase was not enough to deter them from buying the card.

Fare revenue in March was $2.9 million less than predicted: about $236
million compared with about $239 million. In addition to the effects of
the fare increase, bad weather might have decreased ridership.

"What you're really doing is a little crystal-balling as to what people's
buying patterns will be," said Lawrence G. Reuter, the president of New
York City Transit. "You can't be 100 percent accurate in these models."

In an effort to help protect transit revenues, a committee of the
authority's board approved changes yesterday to bring the rules of conduct
for customers in line with a new state law. The law makes it a
misdemeanor, rather than a violation, to sell a ride to another person by
swiping an unlimited-ride card or by tampering with an expired card.