A new traffic signal was installed on Greenwich Street in Tribeca recently—but not where the neighborhood expected it.

The signal went up on Franklin Street, three blocks north of Duane and Greenwich—an intersection that had been the focus of community concern for years and where a light has been promised since October.

Lynn Decker, a Greenwich Street resident, said she was puzzled by the ap­pearance of the light. “My first thought was, ‘Gosh, maybe they made a mistake,’” she said. “Maybe it met some standard they have. I don’t know why they do these things.”

It was no mistake, according to De­partment of Transportation spokes­man Scott Gastel. The Franklin Street light was studied and approved last May, five months before the DOT gave the go­-ahead for the Duane Street signal, Gastel told the Trib. Both locations, according to Gastel, met federal guidelines for installing signals and they are going up in the order in which they were approved. He said the Duane Street light is due to be installed in February.

Approval for the Duane Street light came in October, weeks after a cab grazed a 3-year-old boy on a scooter crossing Green­wich Street with his mother. The incident brought a renewed call from Manhattan Borough President Scott Stringer and other local officials for a light at the intersection.

The DOT said its decision to put a light at the intersection was based on a new study of traffic volume begun before the accident.

Through the urging of the Friends of Washington Market Park, the city had conducted multiple studies of the intersection, each time concluding that the traffic volume did not meet federal guidelines for a traffic signal.

Community representatives had not pressed the DOT for a light at Franklin Street. Kelly Magee, a spokeswoman for City Councilwoman Margaret Chin, said her office was aware that the light was coming but, she added, “we expected the Duane street light to be installed first since we had asked that the installation of that light be expedited.”