Ryan allegedly was driving drunk last October when he crashed on the Long Island Expressway in North Hills.
Officer Joseph Olivieri, a 13-year veteran of the force, was killed by another car as he crossed the expressway to help Ryan.
Prosecutors have said that Ryan's "reckless behavior" led to the 43-year-old officer's death.
The new charges include aggravated vehicular homicide, second-degree manslaughter, first- and second-degree aggravated vehicular assault, second-degree assault, aggravated criminally negligent homicide, criminally negligent homicide and driving while intoxicated.
These charges are in addition to the original charges of second-degree vehicular manslaughter, DWI, reckless driving, reckless endangerment, leaving the scene an accident, speeding and impeding traffic.
The aggravated vehicular homicide charge carries a maximum of 25 years in prison. The assault charge is in relation to injuries suffered by an off-duty NYPD detective who was hurt in the chain-reaction crash.
Ryan pleaded not guilty to the original charges. The defense argued that Ryan's father is in law enforcement, and that he has made all his court appearances and complied with all court proceedings.
Nassau County District Attorney Kathleen Rice said that just before 5 a.m. on October 18, 2012, Ryan was driving his Toyota Camry eastbound on the LIE after leaving a Manhattan club when he struck a livery cab driver at a high rate of speed. The cab driver was able to steer his car off the road, but Ryan allegedly fled the scene despite sustaining significant front end damage to his vehicle. Officials say that his car was so severely damaged that pieces of it were cutting into the roadway as he zig-zagged down the expressway.
Before passing the next exit, Rice said Ryan slammed on his brakes, coming nearly to a complete stop. An off-duty NYPD detective who was driving behind Ryan slammed into the rear of Ryan's vehicle. The detective's vehicle spun around violently and came to a rest facing westbound. He suffered a fractured sternum, multiple fractured ribs and heart palpitations.
Ryan's vehicle spun into the concrete barrier, perpendicular across the HOV lane. Officer Olivieri was the first responder on the scene and blocked off the detective's car in the right lane with lights and sirens before crossing the roadway on foot to Ryan's position in the HOV lane.
A black SUV driving eastbound in the HOV lane approached the scene and slowed to between 37 and 40 mph, but did not see Ryan's vehicle in front of him until the last second. The SUV swerved but struck Ryan's vehicle and Olivieri, who was standing next it. Olivieri died a short time later. Ryan's blood-alcohol content at the scene was between .13 and .14 percent.
"This defendant had every opportunity to prevent this tragedy, from not driving drunk in the first place to pulling over after the initial crash," Rice said. "Yet his selfishness dictated every decision, and now a dedicated police officer and family man is dead. These upgraded charges are indicative of the violence of these crashes and the incredible damage James Ryan has caused. My office will aggressively prosecute this case to ensure that the memory of Joseph Olivieri is honored and justice is done."