SANTA BARBARA COUNTY, Calif. -

"He was irreplaceable, we all have a Matthew-sized hole in our hearts that can never be filled", says Jennifer Passwater who was engaged to be married to Matthew O'Neill, "he would have given the shirt off his back for a friend and now he's given his life so that we can save other cyclists, other pedestrians and other people who have right to be on the road."

Passwater wants the community to know Matthew O'Neill was more than just a 33 year old cyclist from Chula Vista who was struck and killed by a pickup truck while riding in the Santa Maria Valley.

"He was a big brother, a son and was always there for his family", Passwater says fighting back tears, "a friend who went out of his way to make everyone feel competent and appreciated, a soul mate that made me the best version of myself."

O'Neill was ten months away from earning his second PHD in Disabilities and Risk Studies at UC Santa Barbara.

"He planned to be a professor and a researcher", Passwater says, "he wanted to teach teachers like myself how to give a voice to our students that might not be able to speak for themselves. He was a lifelong student dedicated to bringing about positive change for individuals with disabilities."

Passwater says O'Neill chose to ride a recumbent bicycle so he could ride longer distances.

"Riding a recumbent is easier on the body ", Passwater says, "it allowed him to see the world, he had the full life he did because he saw the world on the bicycle."

Matthew O'Neill was riding with others in his cycling club at about 7:30pm on Saturday, August 9 when was was hit from behind by a pickup truck towing a horse trailer on Foxen Canyon Road east of Dominion Road in the Santa Maria Valley

O'Neill died from his injuries in the collision which remains under investigation by the CHP, drugs or alcohol are not considered to be factors in the accident.

"Matthew O'Neill was the consummate randonneur", says close cycling friend Stacy Kline, "he was the soul of Pacific Coast Highway Randonneurs cycling club and he was beloved worldwide."

"He rode every single year, he rode multiple, multiple events", Kline says, "he's an accomplished randonneur riding, 200, 300, 400, 600 and 1200 kilometer rides."

"Matthew was also extremely supportive", Kline says, "he made sure everyone felt successful and that everybody could accomplish their goals while riding these extreme long distances."

Clutching medals he won as an extreme, long-distance cyclist, Kline was riding with O'Neill when he was struck and killed on Foxen Canyon Road.

"Matthew was driving legally and very safely", Kline says, "this was a very preventable accident.

"We are all road users with the same rights and the same responsibilities", Kline says, "we have to take due care when we are driving on the road, its very, very important to take away from this incident that simply changing lanes to pass a cyclist will save someone's life in the future, please, when you see a bicyclist, change lanes to pass a bicyclist, that's all you have to do."

"We have to move forward and remember his legacy and help save more lives", Jennifer Passwater says, "when a steering wheel is in your hands so is your life and the lives of everyone surrounding you.

Passwater and Kline, as well as a growing circle of family and cycling friends, are wearing green ribbons in memory of Matthew O'Neill.

"Green was Matthew's favorite color", Passwater says, "he wouldn't want us to sit alone in the dark and cry about his death, he would want us to make something positive about it."

"To do something, to help spread the word, to help save lives, we have to make something out of this so its not in vain", Passwater says, "to help spread awareness of the law and common sense when you are behind the wheel of a vehicle and to change a lane to save a life".

There is a memorial Facebook page for Matthew O'Neill,  "Remember Matthew: Change Lanes to Pass a Cyclist"