“He said that when we got to 1,000 coasters, we’d stop,” she said, “and conveniently, he forgot.”

They visited 125 last year, Mr. Lewison said, and this year’s expeditions have ranged from New Zealand to the Jersey Shore. In coming months, they plan on hitting amusement parks in the Middle East and Vietnam, not to mention the Halloween festivities at Great Adventure in New Jersey.

They have traveled to China six times and ridden more than 150 coasters there, said Mr. Lewison, who recently tried planning a marathon trip to a series of obscure Chinese parks involving constant flights.

“But my wife said, ‘We’re going to die in a plane crash and people will say, ‘What were they thinking?’” he said

Mr. Lewison grew up in Englewood Cliffs, N.J., cutting his teeth on smaller rides at nearby Palisades Park — which is long gone — and then on coasters such as Lightnin’ Loops at Six Flags Great Adventure in New Jersey, the Dragon Coaster at Rye Playland in Westchester County, and the Cyclone in Coney Island.

His obsession blossomed by age 13 when he traveled to Busch Gardens Williamsburg, Va., and rode the Loch Ness Monster 22 times in one day, he said.

His coaster craze cooled after hearing about the fire in 1984 that killed eight teenagers at the Haunted Castle at Six Flags, but it resurfaced while he pursued a doctorate in business in the 1990s at the University of Pittsburgh, thanks to the coasters at nearby Kennywood amusement park.

In his Theme Parks class last week, he apologized for not being quite up to speed. Relatives were staying with them in their modest apartment in Forest Hills, Queens, to attend the U.S. Open tennis tournament, he explained, “so I can’t get any work done.”