Pedestrians prepare to cross York Avenue at East 79th Street, when traffic nearest to them is stopped but traffic going north continues. View Full Caption DNA/Shaye Weaver

YORKVILLE — One man can truly make a difference.

A designated left turn at East 79th Street and York Avenue — which locals say has been putting pedestrians at peril since it was implemented in 2009 — was installed there because one driver wrote a letter to the Department of Transportation requesting it, the agency revealed during a Community Board 8 committee meeting on April 6.

The DOT Borough Commissioner Margaret Forgione admitted the agency had received a letter from a citizen complaining that it was hard to make a left turn west onto East 79th Street from York Avenue — prompting the department to analyze the intersection and to tweak the signal.

All this was done without input from the community, according to the CB8 committee chair Scott Falk.

"It seems odd that one person writing a letter would be able to have a light installed," said CB8 chairman Jim Clynes.

The DOT refused to provide a copy of the letter or reveal the identity of the writer, but a spokesman said it is not uncommon for the DOT to conduct a signal study at the request of one person.

Now, seven years later — after 17 pedestrian injuries and one death at that intersection, according to the city's Vision Zero map — the DOT is agreeing to change the signal back.

Under the current rules, southbound traffic on York Avenue gets the red light while those going northbound are free to take a left turn or go straight.

This makes it dangerous for pedestrians, especially those unfamiliar with the pattern, who locals say use their "New York instinct" to assume they can walk when they see cars stopped at a red light.

Many members of the board and the community said they've pulled pedestrians out of harm's way as northbound traffic nearly hits them. It's become a daily occurrence, they say.

The committee voted in favor of a resolution to ban the left turn there, and Forgione agreed to have it done. The traffic signals will be reset so that both directions on York Avenue get red and green lights at the same time, she said.

"We have to do it," said Alan Friedman, a resident and personal injury lawyer. "This is a life-and-death issue. It's that simple."

Forgione estimated that it would take roughly two months to make the change.