Many wore dress blues as they did for the March 2011 memorial for his academy classmate, Nassau officer Geoffrey J. Breitkopf.
A bagpipe team blared and cruisers slowly rolled by just as with the funeral in February 2011 for another academy classmate of Olivieri, Nassau patrolman Michael Califano.
Olivieri's funeral service was the latest example of the unpredictable and deadly nature of police work. It even brought out relatives of others killed on duty.
"We just want to let the family know that we are here," said Susan Ciano, of Bayport, whose husband, Glen, a Suffolk County police officer, was killed in 2009 when his cruiser was struck by a drunken driver. "I just want to let the family know that we have walked in their shoes."
Olivieri was buried later in Holy Sepulchre Cemetery in Coram.
Ciano was among the throng who packed St. Joseph's Roman Catholic Church in Ronkonkoma to remember Olivieri, who was struck by a passing motorist and killed early Thursday morning near Exit 35 of the Long Island Expressway in North Hills.
Like Breitkopf and Califano, Olivieri was appointed to the Nassau Police Department in December 1998. On Monday, he was remembered as they were -- a dedicated cop whose presence on the job will be impossible to replace.
"We're all feeling a sense of loss right now, and these have been difficult days to get through," said Officer Robert Delsignore, who also worked in highway patrol. "But when we really feel the deep sense of loss is when we go back to work and our friend isn't there anymore."
Delsignore held up a photograph with half a dozen or so police officers -- among them Olivieri and Califano.
Olivieri was hit on a stretch of the same expressway and just four exits from where Califano was struck and killed in February 2011.
In the latest crash, Olivieri was responding to a predawn wreck caused by an alleged drunken driver, James Ryan, 25, of Oakdale. The officer was hit by a passing sport utility vehicle about 4:45 a.m. after he had gotten out of his cruiser on the eastbound LIE. He was pronounced dead a short time later at North Shore University Hospital in Manhasset.
Ryan has been charged with vehicular manslaughter, driving while intoxicated and other crimes related to the crash.
The SUV's driver is not facing charges related to the crash.
Olivieri spent five years with the NYPD before joining the Nassau County Police Department. He leaves two children, Amanda, 21, and Daniel, 18.
Officers from more than 100 law enforcement agencies across the state and beyond paid their respects Monday. Politicians, including Nassau County Executive Edward Mangano and Nassau District Attorney Kathleen Rice, whose office is prosecuting Ryan, also attended.
Police union president James Carver said Olivieri's death is a stark statement to drivers: Slow down.
"I think that is the most important message here right now, you know, go slow for Joe," Carver said before he headed into the church. "If you see something on the side of the road make sure you slow down and [make sure] you're aware of what's going on in front of you."
The Rev. Michael Maffeo, pastor of St. Joseph's Catholic Church in Ronkonkoma, told Olivieri's children that they should continue to see their father in the work of the living.
"Don't look for Joseph among the dead," Maffeo said, looking directly at Olivieri's children in a church packed with police officers. "He is among the living, doing all his wonderful work in the reflection of his love for God."
With Maria Alvarez