A City Hall proposal to force a 20 mph speed limit on Boston drivers is ?unlikely to slow them down, traffic engineers say.

“It would be a mistake to think that lower speed limits will instantly slow people down,” said Peter Furth, a professor of civil engineering at Northeastern University.

The City Council held a hearing yesterday on Councilor Frank Baker’s proposal to lower Boston’s default speed limit for thickly settled areas to 20 mph from 30 mph, as a way to cut traffic injuries and deaths.

Twenty-three people died last year in Boston traffic accidents, including crashes with cars, pedestrians and bicycles, according to Boston Transportation Commissioner Gina Fiandaca. A total of 4,285 crashes required an EMS response. Six people have died so far this year.

“In spite of our best intentions and labor, providing safe streets for all people continues to be a challenge for Boston,” Fiandaca said.

Several city councilors at the hearing yesterday offered their support for the measure — including council President Michelle Wu, Baker, Michael Flaherty, Salvatore LaMattina, Timothy McCarthy, Matt O’Malley and Tito Jackson — and many said speeding is the top complaint they get from residents.

“Having young children, I can confirm 30 miles per hour is too fast in our neighborhoods,” Baker said.

LaMattina concurred, say?ing, “This is a no-brainer. We have been trying to do this for many years.”

However, pedestrian fatality rates in the Boston metropolitan area — 0.99 deaths annually per 100,000 people from 2008-12 — are below other large cities, such as New York City, with 1.76 deaths, and San Francisco, with 1.36 deaths per 100,000.

Pedestrian deaths in Boston have ranged from four to 12 a year from 2010 through 2014, according to police statistics, while ?bicycling deaths have ranged from one to four a year.

Baker’s proposal seeks to petition the Legislature to let Boston change its default speed limit, which is now controlled by state law. While the city has the authority to lower speed limits in areas where it has done traffic studies, the proposal argues it would be too costly to study the ?entire city.

Promoters of the measure say slower traffic could be the difference between life and death, as studies show a person hit by a car at 30 mph has a 50 percent risk of severe injury or death, while that risk drops to 18 percent at 20 mph. New York City reduced its ?default speed limit in ?November 2014 to 25 mph from 30 mph to reduce pedestrian deaths.

Furth said that although speed limits are not “self-enforcing,” they are a useful tool for residents ?demanding that the city take action against speeding in their neighborhoods.

Northeastern civil engineering professor Daniel Dulaski said a more effective approach than lowering the speed limit is to ?redesign roads to slow down drivers — by narrowing lanes, adding bike lanes, changing road grades and adding speed bumps.

“Can you ticket? Sure. Will it have a lasting effect? Nope,” Dulaski said.

“To get to speeds that are liveable for all users, you ?really need to think about, how do we change the road environment?”

Dulaski said, “It’s at the forefront of life now ?because people are tired of crossing streets and fearing for their safety.”

Chris Osgood, Boston’s chief of streets, said the Boston Transportation Department is experimenting with ways to slow traffic by making changes to streets such as adding speed bumps in the Talbot-?Norfolk Triangle in Dorchester and the Stonybrook area in Jamaica Plain.