New York City’s traffic deaths were the lowest in its history last year, Mayor Bill de Blasio announced Tuesday, but there is still significant work ahead to make trouble spots less dangerous and protect vulnerable groups such as senior-citizen pedestrians.

“The work is not over until no New Yorker loses their life, no New Yorkers loses a loved one walking, or cycling, or driving on our streets,” de Blasio said in a school on Queens Boulevard about the “Vision Zero” safety initiative announced early in his administration.

The mayor announced plans for additional measures this year for the administration’s plan to end traffic deaths. The name “Vision Zero” comes from a traffic safety planning model developed in Sweden to eliminate traffic casualties.

The city will redesign another stretch of Queens Boulevard, add protected bike lanes on thoroughfares such as Amsterdam Avenue on the Upper West Side and do other street redesigns in the Bronx, Staten Island, and Queens.

Citywide, a total of 231 people were killed in crashes last year — 26 fewer than in 2014. Pedestrian deaths dipped slightly, from 139 in 2014 to 134 in 2015. The most significant plunge was in the number of motorcyclists killed, which fell by 15 — from 37 in 2014 to 22 in 2015.

Seniors were 38% of the city’s fatalities last year, even though they represent only 13% of the population. The NYPD will target reckless drivers near senior centers and areas with high numbers of elderly residents between Jan. 25 and Jan, 31 in their first senior-focused enforcement initiative.

Cycling deaths dropped from 20 in 2014 to 14 this year.

The number of motorists and passengers who died last year was 61, the same as the year before. The city Department of Transportation estimates that almost 40% of drivers killed in recent years had been drinking before their crashes.

The MTA has been trying to reduce bus fatalities. It is testing an audio alert to warn pedestrians and collision avoidance technology. A spokesman said that there were seven pedestrians killed by MTA buses in 2015, down from eight in 2014. The MTA did not provide requested data on other fatal bus accidents, such as collisions with cars.

Queens had the most traffic deaths, at 73, but only 33 were pedestrian deaths. Brooklyn saw both its overall traffic deaths decline from 81 to 69, and pedestrian deaths decrease slightly.

The 10 fatalities in the 109th precinct in Queens, which includes Flushing and Whitestone, were the most in any precinct in the city, according to preliminary information from the NYPD. The most recent death was a female passenger killed when the driver in her car crashed into an empty school bus.

Brooklyn’s 61st precinct, which covers Sheepshead Bay and Gravesend, had seven deaths.

The NYPD has focused on six types of moving violations, according to the review. Speeding tickets went up about 14% from the year before, to 134,000. Summonses for failing to yield increased by 18.6%. Texting drivers were given about 26% more tickets than in 2014.

De Blasio’s administration credited the drop in motorcyclist deaths to education and enforcement, which includes moving summonses and equipment violations.

The NYPD’s Collision Investigation Squad examined 407 crashes that had fatal or serious injuries, according to the review, leading to summonses or criminal charges against 102 drivers.

Keegan Stephan, an organizer with the safe street group Right of Way, said many more crashes should be investigated to gather information on causes that can help prevent future ones. He called enforcement “the weakest link in Vision Zero.”

Transportation Alternatives’ executive director Paul Steely White praised de Blasio for setting the right priorities.

“He also made a very clear statement that saving lives on our streets is more important than potential impacts to traffic and parking.”

Frank Gulluscio, district manager for Forest Hills’ community board, was impressed with the work being done to make Queens Boulevard safer. The city has redesigned a stretch of the thoroughfare, which was dubbed the “Boulevard of Death” decades ago for its high fatality rates, from Roosevelt Avenue to 73rd Street, and will do between 74th Street and Eliot Avenue next.

“I think everyone is on the same page at this point,” said Gulluscio. “People are talking about Queens Boulevard. It’s been talked about a lot, but now it’s sinking in.”