Boston is set to lower its speed limit in Jan.

BILL BRETT FOR THE BOSTON GLOBE/File

The City Council on Wednesday finalized a measure to reduce Boston’s default speed limit from 30 to 25 miles per hour on Jan. 9.

Mayor Martin J. Walsh, who had pushed for the change, called the measure an important step toward reducing the risk of injuries and fatalities on the city’s roads. Boston has set a goal of eliminating traffic-related deaths by the year 2030.

“I am pleased that our hard work and commitment to creating safer roadways for all users by reducing the default speed limit to 25 miles per hour will become a reality in January,” the mayor said in a statement.

“This is an important milestone in our Vision Zero efforts of bringing the number of traffic-related deaths to zero, and with approval of this petition we are one step closer to achieving that goal,” Walsh added.

Once the change goes into effect, drivers will not be allowed to exceed 25 miles per hour on any road unless a different limit is otherwise posted.

Boston was allowed to make the change under a statewide measure that authorizes municipalities to lower their default speed limits.

Somerville made a similar change recently. On Nov. 7, the city dropped speed limits across the city to 25 miles per hour, unless otherwise posted.

At least 17 people have died in car accidents this year on Boston’s streets — 12 of whom were pedestrians. In a statement, Walsh’s office expressed hope that the stricter rules would lead to fewer deaths, because crashes become more deadly at higher speeds.

State Representative Dan Hunt of Dorchester, who pushed in the Legislature for the statewide change, said he hopes the change will improve the quality of life in city neighborhoods.

“Traffic congestion and speeding cars are among the most common issues I hear about from constituents,” he said in a statement. “Taking this one action has the potential to greatly improve pedestrian safety in our neighborhoods.”