The Long Island Rail Road’s $1 billion safety system, designed to prevent crashes and save lives, has failed in its first tests.

MTA officials said Positive Train Control, or PTC, procedures has been tested 31 times since February. They said the software was tested both in the factory and on the LIRR's Port Washington branch.

PTC’s job is to automatically bring to a halt any train that violates a stop signal. Of those 31 times, officials said the system passed 13 but failed 16 times.

"Our system is significantly more complicated than anybody else's system, specifically moreso than the Amtrak system for which the PTC was designed," said MTA board member Mitch Pally. "There is no PTC to buy off the shelf. It has to be personally changed for every system, and our system is the most complicated system there is."

Pally said it’s much easier to implement PTC on Amtrak or other rail systems that go in a straight line for 30 miles at a time, as opposed to the multiple stops along the LIRR.

Investigators have said that PTC could have prevented a number of recent fatal train accidents, including a Metro-North train derailment in the Bronx that killed four people.

“I think it takes a lot of testing and research until they get it right," said Pally.