The 50 percent rule concerns a car accident caused by a negligent or careless driver in a situation where you were also at least partially to blame. The state of Texas uses modified comparative negligence law to determine damages in an auto accident claim. This means that you can claim compensation from the other driver, so long as you are 50 percent or less at fault for the accident. Once you are found to be 51 percent or more liable for the accident, you will not be able to file a claim against the other driver.