Lower speed limits are coming soon to New York City streets. Mayor Bill de Blasio signed legislation Monday reducing the speed on most city streets from 30 miles an hour to 25, starting November 7.

“We strongly believe that death and injury from vehicle crashes is not only unacceptable, it is avoidable,” de Blasio said. “Data show time and time again, speed is the core culprit.”

Pedestrians struck by cars going 25 are half as likely to die as those struck at 30 miles per hour, de Blasio said. “This change, in just 5 miles an hour, makes a fundamental difference in people’s lives.”

Approximately 95 percent of city streets now have a 30 mile-an-hour limit. The new lower limit will be in place on 90 percent of city roadways. The speed limit reduction was a centerpiece of the mayor’s Vision Zero plan to eliminate traffic deaths by 2024.

NYPD officers may not ticket drivers going 26 or 27, just over the new limit, NYPD transportation chief Thomas Chan said. “But we definitely will be out there,” he said, and ticketing will be at the officers’ discretion. The city’s speed cameras will shift to the new speed limit starting on November 7^th. The cameras issue $50 tickets when drivers are going more than 10 miles over the posted speed.

The bill signing took place at the corner of Delancey Street and Suffolk Street in lower Manhattan, where 12-year-old Dashane Santana was killed in January 2012. Amy Cohen, whose son Sammy Cohen-Eckstein was struck and killed by a car in Brooklyn last year, said that if the cars that hit Sammy and Dashane had been going 25, they would “likely still be alive today.”

“The change to a 25 mph speed limit is a life-saving change. It is not about raising revenue,” Cohen said. “At 25 miles per hour, drivers have more time to react when the unexpected happens. And if a crash cannot be avoided, it’s much less likely to be fatal.” Being struck by a car is the leading cause of death for children under 14 in New York City.

Some 3,000 new signs will be installed across the city, at a cost of $500,000, according to the city’s Department of Transportation. The NYPD also has a new Vision Zero van.