On May 18, 2006, plaintiff Christine Nelson, a home health care aide in her 30s, was involved in a rear-end collision on the off-ramp of Interstate 10 in Clairmont. She was struck by a truck driven by Nathan Reynolds, an employee Geo Science Inc. Nelson claimed to her neck, lower back and left knee. On April 2, 2007, Nelson was involved in another rear-end accident at the intersection of Alder Avenue and E Base Line Road. This time, she was struck by a van driven by Mark Martinez, an employee of the San Bernardino Sheriff’s Department. She claimed aggravations of her previous back . Nelson sued Reynolds and Geo Science Inc., and brought a separate action against Martinez and the county of San Bernardino. The matters were ultimately consolidated into one case. Nelson alleged that Martinez and Reynolds were negligent in the operation of their respective vehicles. She also alleged that the county was vicariously liable for Martinez’s actions and that Geo Science was vicariously liable for Reynolds’ actions. The defendants admitted liability for their respective accidents, and the matter proceeded to a trial on causation and damages., Nelson went to an emergency room the day after the May 2006 accident with complaints of left hip pain. She ultimately began treating with a few months of physical therapy for to her lower back, neck and left knee. She then started treating with an orthopedist in October 2006 and underwent an MRI of her lower back. Additional physical therapy was recommended, but Nelson decided to treat with a neurosurgeon. She subsequently underwent a discogram that revealed lumbar disc protrusions at L4-5 and L5-S1. In March 2007, Nelson underwent decompression surgery and followed up with more physical therapy. Following the April 2007 accident, Nelson was taken by ambulance to an emergency room. She claimed an aggravation of her lower back injury, and continued to treat with an orthopedist and physical therapy. Nelson further treated for a left knee injury in 2009 and underwent two arthroscopic surgeries to treat a torn meniscus. Nelson claimed that she still experiences pain and discomfort in her lower back and left knee, which affects all her normal activities, including walking, exercise and dancing. She also claimed she has to use a cane to ambulate sometimes, as well as a knee brace, and may require another knee surgery. Thus, Nelson asked the jury for $150,000 in total damages at trial. Defense counsel contended that neither accident caused Nelson any serious injury, since the first collision was at a speed of 5 mph, while the second one was merely a “roll and tap.” They argued that there was no mechanism of injury to the plaintiff’s lower back and that her decompression surgery was unrelated to the accident. Defense counsel further claimed that Nelson’s knee injury and surgeries were totally unrelated to either accident.