Beginning in July, transit police will randomly stop riders on Boston's subways and commuter trains to search bags and packages.
Transportation officials said the new procedure, which will include the use of bomb-sniffing dogs, was largely due to the Madrid train bombings.
In addition, all 247 uniformed Massachusetts Bay Transportation Authority (MBTA) police officers will be employed.
"We want to do this to encourage people to feel safe on the MBTA, to utilize public transportation," said MBTA Police Chief Joseph Carter in a Boston Globe report.
The new search policy will be in place for the July Democratic Convention, when inspections will increase.