Using authority granted under a law just signed by Gov. Charlie Baker, Boston Mayor Martin Walsh plans to work with the city council to lower the default speed limit in Boston from 30 miles per hour to 25 miles per hour.

"We know that lower speed limits are an important tool in reducing fatal and serious crashes and creating safer streets for people of all ages and abilities who are walking, driving, and bicycling," Walsh said in a statement. "A lower speed limit in Boston would be a major early accomplishment for our Vision Zero goal: bringing the number of traffic deaths and serious injuries to zero by 2030."

Outside section 193 of a municipal government reform bill (H 4565) signed Tuesday by Baker authorize cities and towns that accept those sections to set a 25 miles per hour speed limit "inside a thickly settled or business district in the city or town on any way that is not a state highway."

Section 194 permits cities and towns to establish "safety zones" where the speed limit could be reduced to 20 miles per hour.

Boston Transportation Commissioner Gina Fiandaca, who has worked in that department since 1990, will work on the issue with the mayor and the city council.