LOS ANGELES (KABC) -- Joining the throngs of bicyclists at CicLAVia, Carol Um's morning of fun turned into a calamity.A collision with another bicyclist left her with irreversible brain damage, facial paralysis and a fear that a hazard is lurking around every corner."It changed everything. It changed everything," Um said.The city of Los Angeles shuts down streets to car traffic and invites bicyclists and walkers to enjoy the city sights on those closed roads. But that was not enough to protect Um.The collision was captured on a security camera. A man on the sidelines rode toward her lane like he was going to join the flow, but instead he crossed her path, clipping her front tire. Um's head hit the pavement. Her husband could not revive her."When I saw blood coming out of her ear, I thought the very worst. She had died," Jae Doe said.With a lawyer the couple is now suing the city of Los Angeles, alleging negligence. The city-sponsored event touts the car-free environment. Many people do not wear helmets. Um did not either. She didn't anticipate the actions of a careless rider."When you have people going all different directions without direction or control, you are creating an environment where a catastrophic event is going to occur," her attorney Doug Rochen said.CicLAvia said Friday that safety is their top priority. And participants should look at their website for safety tips - among them is to wear a helmet and exercise care.Um believes more is needed to prevent what happened to her. The young couple has exhausted their savings, and the future needs of Um are uncertain.Um's mission now is urging people to be cautious no matter what they are doing."You have to be aware of everything. Just be safe, keep your eyes open," she said.