Several different types of head injuries and TBIs can come from bicycle-car accidents. There can be skull fractures, which are dangerous because if the fractures are separated or big enough, they can penetrate the brain. In these incidents, lacerations to the head and blood clots can also happen, as can nerve damage. A concussion is a common injury from a bicycle accident, and it can happen with or without a helmet. While many people consider concussions “mild” injuries, modern medicine takes all brain injuries seriously, and so should you. Even if you feel disoriented and are tempted to wait it out, always see a doctor instead. A seemingly minor concussion can worsen quickly, and you want to begin treatment as soon as possible. Concussion effects can last for months or even years for some victims, so this is certainly not a “mild” injury. A severe TBI usually involves unconsciousness for over 24 hours and signs of apparent injury on neuroimaging tests. Once they wake, a victim can be visibly irritable, unable to understand or think clearly, and may have hearing or memory problems. All of these are possible in bicycle accidents involving motor vehicles.