CHICAGO (CBS) — A mistake turned fatal Sunday afternoon on the Dan Ryan Expressway, when a driver cut off an off-duty police officer who was riding a motorcycle.

CBS 2’s Dana Kozlov reports 28-year-old Officer Tito Rodriguez – who was a new recruit still serving as a probationary officer, with less than 18 months on the job – was heading south on the Dan Ryan near 69th Street when he collided with a car.

Rodriguez’s childhood friend and roommate Roger Steele was shattered by his loss.

“He was just honest, loyal, beyond dependable,” Steele said.

(Supplied to CBS)

(Supplied to CBS)

Illinois State Police said 50-year-old Donald Anderson was driving a 2007 Pontiac coupe and was trying to make a sudden lane change to exit the Dan Ryan at 71st Street, when he cut off Rodriguez.

Rodriguez was unable to avoid hitting the back of the Pontiac, and slid at least 40 feet on the pavement after the collision. State police and witnesses said he was not wearing a helmet.

“He did not have on a helmet, and it was two other gentlemen on a motorcycle with him – that was on different motorcycles – and neither one had on helmets,” witness Tracy Johnson said.

(Credit: CBS)

(Credit: CBS)

Investigators spent hours at the scene after the crash. Anderson was issued two traffic citations – for making an improper lane change and not carrying valid insurance. No criminal charges have been filed.

Steele said it was Rodriguez’s dream to become a Chicago police officer, and he was looking forward to what was ahead.

“He’s irreplaceable; a good friend,” Steele said. “I don’t know what life is going to be without him.”

Police Supt. Garry McCarthy said, “We are truly saddened by the loss of Officer Tito Rodriguez who perished in today’s tragic accident.

“On behalf of the entire Chicago Police Department, our thoughts and prayers are with his family during this difficult time. Whenever we lose one of our own, it has an effect on each of us, and we will be sure to honor Officer Rodriguez’s memory and spirit appropriately.”