– Fortified by fences and patrolled by more armed personnel, schools will open their doors to students for the start of the new year with a heightened focus on security intended to ease fears about deadly campus shootings.

The Feb. 14 massacre in Parkland, Fla., unnerved school administrators across the country, who devoted the summer to reinforcing buildings and hiring security.

In Florida, armed guards will be posted on almost every campus. In Indiana, some schools will be getting hand-held metal detectors. In western New York state, some schools plan to upgrade their surveillance cameras to include facial recognition.

Six months after the rampage at Marjory Stoneman Douglas High School in Parkland, public schools have embraced expensive and sometimes controversial safety measures.

“If we can find the resources, and if our taxpayers are willing to support us, then we will do everything in our power to try to create a sense of normalcy and ease,” said Donald Fennoy, superintendent of the school district in Palm Beach County, Fla., which borders Parkland.

Palm Beach is nearly doubling its school police force — and asking voters to support a property tax increase to help pay for it. But, Fennoy added, “we know that schools are still the safest places for the majority of our kids.”

The wave of efforts marks the latest escalation of security enhancements prompted by horrifying and highly publicized school attacks.

Schools opened with metal detectors this week in Marshall County, Ky., where two students were killed at a school shooting in January. New York City has considered expanding the use of metal detectors, though some students worry they disproportionately target schools with students of color.

No policy has caused more debate than allowing teachers to carry weapons, a proposal pushed for years by the National Rifle Association and supported by President Donald Trump in February.

At least 10 states allow districts to arm teachers and other staff members. One of the states is Texas, where a shooting at Santa Fe High School in May left 10 people dead. Gov. Greg Abbott responded by proposing more spending on police officers and armed guards on campus; the Santa Fe school district accepted donations of metal detectors, protective vests and other police equipment.

A law Florida passed after the Parkland shooting requires armed security guards at every school and expands mental health funding for schools. But getting those services into place will take time, administrators from several school districts acknowledged.

When students arrive at Stoneman Douglas for the new school year Wednesday, security changes will be evident. New chain-link fences ring the inside of campus. More surveillance cameras are mounted high up on the walls. Classroom doors have been outfitted with handles that lock automatically.

Visitors will have to be buzzed in. Three school resource officers — instead of only one — will be on staff.

What will matter most in Parkland and elsewhere, however, will be what school districts do behind the scenes, said Alberto Carvalho, superintendent of the neighboring Miami-Dade County Public Schools. The most effective way to prevent a tragedy is by giving school communities a way to report concerns about troubled students and then offer those students the help they need, Carvalho said.

“After all of this, the strongest tool we have available to use is low cost but highly effective: It’s the level of alertness of parents, students and community members,” he said. “We really mean it when we say, ‘If you see something, say something.’ ”