On March 15, 2017, plaintiff Mohammad Mashadi, 40, a livery vehicle’s driver, was driving in San Francisco. When he reached the intersection of Market and Polk streets, he stopped at a red traffic signal. Before he could resume travel, his vehicle’s rear end was struck by a vehicle that was being driven by Max Ivey. Mashadi claimed that he suffered of his back, his head and his neck. Mashadi sued Ivey. The lawsuit alleged that Ivey was negligent in the operation of his vehicle. Defense counsel conceded liability. The trial addressed damages., After having returned to his home, Mashadi visited a hospital. He claimed that he was suffering pain related to the accident. He underwent minor treatment. Mashadi ultimately claimed that he suffered a protrusion and an annular-tissue tear of his L5-S1 intervertebral disc, an injury of his neck, a concussion, and resultant damage of his brain. He claimed that his brain’s injury caused residual effects that included headaches, impairment of his memory and impairment of other elements of his cognition. Mashadi underwent chiropractic manipulation and the administration of two painkilling injections. Mashadi claimed that his prevented his performance of about three months of work. He also claimed that his back and neck remain painful, that he suffers ongoing impairment of his cognition, and that he requires lifelong treatment including chiropractic manipulation, physical therapy, psychotherapy, the administration of painkilling injections and ablation of problematic spinal nerves. Mashadi sought recovery of past and future medical expenses, past lost earnings, and damages for past and future pain and suffering. Defense counsel contended that Mashadi did not suffer an injury of the brain. He suggested that Mashadi’s ongoing symptoms are products of Mashadi’s work, which often involves prolonged periods in which he is driving a vehicle. Defense counsel conceded that Mashadi’s neck pain was related to the accident, but the defense’s expert orthopedist contended that Mashadi’s torn annular tissue was a degenerative condition. The expert opined that Mashadi’s lumbar injury was nothing more than an injury of soft tissue, though he also opined that Mashadi’s treatment was appropriate. Defense counsel also contended that Mashadi does not require further treatment.