It is unclear, however, whether the signs are in error at all.

Since these signs sit on the west side of Fifth Avenue, they are technically in the western zone of the street grid. So can West 84th Street exist on the west side of Fifth Avenue, even if the street itself begins on the other side of Central Park?

The answer, steeped in the arcane history of New York’s streetscape, is hazy, even among historians. But the dispute points to the prevailing mysteries of Manhattan’s street grid, which, despite celebrating its 200th birthday on Tuesday, can continue to flummox.

Samuel I. Schwartz, a former transportation commissioner and a longtime authority on New York’s streetscape, said he believed the city’s bus stop signs were, in fact, correct.

On that side of the street, “you are on the West Side of Manhattan,” Mr. Schwartz said.

“Let’s be pure about it,” he continued, “and keep Fifth Avenue as the dividing line.”

Mr. Stringer, however, insisted that the signs were confusing at best and a danger at worst.

“These are nonexistent streets, which do not actually appear until you’re standing on the other side of Central Park,” he said.