The state Thruway Authority acknowledged on Tuesday that it has found another technological foul-up with its E-ZPass system, this time on Grand Island.

An authority spokeswoman said more than 2,400 motorists may have been wrongly cited for speeding because of problems with its speed detection equipment in two E-ZPass lanes on Grand Island.

The authority is sending out apology letters to motorists accused of speeding through the lanes on Grand Island between April 27 and June 22.

Tuesday’s announcement comes on the heels of an announcement last week that 3,600 people had been wrongly cited for speeding through the E-ZPass lanes at the Dunkirk- Fredonia State Thruway exit.

“The Authority regrets that this [Grand Island] matter was not detected sooner,” Kimberly Chupa, a Thruway Authority spokeswoman, told The Buffalo News.

With 6,000 Western New York motorists wrongly accused of speeding in recent weeks, how dependable is the E-ZPass system?

For the most part, very dependable, Chupa said.

“With any technical equipment, there are instances of malfunctions,” she said. “However, the Authority believes using E-ZPass is a proven, reliable and convenient method to pay tolls, in addition to reducing traffic congestion.”

In response to questions from numerous motorists and The News, the authority said some new speed detection equipment that was being tested at the Grand Island bridges may have caused drivers there to be cited for speeding.

About a dozen drivers told The News that they were cited for zooming through the E-ZPass lanes at 30 to 40 miles per hour, when actually, they were driving at speeds closer to 5 mph.

That equipment, which was being tried for the first time by the authority, is no longer being used, Chupa said.

“Upon receiving several inquiries from E-ZPass customers who were issued speeding violations . . . the Authority conducted a thorough review of its data and determined the accuracy of the data collected by the new speed detection equipment was questionable,” Chupa said.

“As a result of the questionable accuracy, the Authority is considering the data for this time period unreliable for all vehicle classes that traveled through [E-ZPass] Lane 1 and Lane 7 . . . As such, any speed issues during this time period in the specified lanes are being dismissed and each customer will be getting a letter to that effect, apologizing for the error.”

Grand Island drivers were upset when they received letters from the Thruway Authority threatening to suspend their E-ZPass privileges or, in some cases, revoking them.

Asked for some statewide figures, Chupa said that in 2008, motorists drove through E-ZPass toll booths more than 158 million times. Each of those drive-throughs is considered an E-ZPass transaction.

In 221,304 transactions, motorists were cited for speeding.

“That means there were speeding violations cited in well under one percent of these transactions,” Chupa said.

Chupa said she could not provide figures on how many motorists were incorrectly cited for speeding in 2008.

The problems in Grand Island and Fredonia are unrelated to each other, and problems with the E-ZPass system are not widespread, Chupa said.

The Grand Island inaccuracies were caused by new equipment that was being tested, while the inaccurate citations in Fredonia were caused by existing equipment that malfunctioned, she said.