The City Council wants to allocate $9.9 million to replace bullet-resistant vests for about half the officers in the Police Department.

State-of-the-art Level 3A bulletproof vests would be purchased for about 18,000 officers who are now wearing Level 2 vests. The other 18,000 officers already have been issued Level 3A vests. The level of the vests is based on bullet-stopping capability. The council speaker, Christine Quinn, said the council’s proposal is feasible because the price tag represents only 0.27% of the Police Department’s $3.7 billion budget. The council’s Finance Committee chairman, David Weprin, added that $9.9 million represents a fraction of the council’s total budget.

On Thursday, the council will present its response to the $52.2 billion budget the mayor announced in January. When asked to elaborate about other specifics in the budget proposal, Ms. Quinn’s spokeswoman, Maria Alvarado, said, “This is the only one we’re focusing on today.”

The city has a responsibility to pay police officers, “train them, and protect them,” the president of the Patrolmen’s Benevolent Association, Patrick Lynch, said.

The Level 3A vests provide greater coverage area in the chest and along the sides of the body. The vests cost $560 each.

The death in November of Officer Dillon Stewart, who was shot in the left armpit area, a spot the vest does not cover, provides an example of how a vest with greater coverage might have saved a life, Ms. Quinn said. Stewart was allegedly shot and killed during the pursuit of a motorist who had run a red light. “Had there been a stronger vest, it might have been preventable,” Ms. Quinn said.

The chairman of a company specializing in military supplies and security assessment offered a different opinion. “There’s no vest that will protect you against that,” the chairman of the Cavalry Security Group/U.S. Cavalry, Patrick Garvey, said. “That’s just an unfortunate luck of the draw.”

The Police Department has required that officers wear the protective vests since 1988. “The Police Department wants the best equipment possible for all its police officers,” Police Commissioner Raymond Kelly said in a statement.

One benefit of the newer vests is that they provide detectives with protection from today’s “high-tech weapons,” the president of the Detectives’ Endowment Association, Michael Palladino, said.

At a question-and-answer session yesterday preceding the 185th Greek Independence Day Parade, Mayor

Bloomberg fielded a question about the council’s budget proposal. “The Police Department will decide what’s in their interest,” Mr. Bloomberg said. “They’re the ones that know what’s best to protect the brave men and women who are out there every day putting their lives at risk.”

A former firearms instructor, Robert Clark, said the Level 3 vest is “top of the line as far as bullet-resistant vests go.” If an officer is shot, “It is still going to hurt like hell. But it’s not going to pierce the armor.” Because it is a heavier vest, it is more uncomfortable and harder to conceal, he said.

Since the Level 3A has more heft, it might be better suited for special operations units or officers working on short-term assignments, Mr. Garvey said.

Bullet-proof vests have been credited with saving lives. Between 1988 and 2005, they prevented the deaths of about 60 officers, police said, although more lives were saved in the 10 years prior that vests were used but not required.

“The one thing cops have found out – these are lifesavers,” Mr. Garvey said. When asked if the officers will wear them in extreme temperatures, he said, “They’ll wear them – cold, summer.”