Yes, you can! Sometimes two or more acts or failures to act combine in an accident. In some states, unless the defendant had the last clear chance to avoid the wreck, for example, the plaintiff's case is dismissed.
But in California, we use the pure comparative negligence rules. So here, your award is simply reduced based upon your percentage of fault.
A and B are in a car crash. A is following too closely, and rear ends B. But B gets out of the car in traffic and gets run over by an oncoming California Highway Patrol police cruiser. B dies.
The jury would award the survivors of B for the vehicle damage and whiplash. But B's estate would need to sue the CHP for the death. However, getting out of a car in oncoming traffic would mean that B was partially at fault.
Hence, under pure comparative negligence principles, the jury may find B 50% at the blame. So if the court awards B $1 million dollars against the CHP, the family would only get $500 thousand dollars. Is this making sense so far? (If you're confused go here to read more about pure comparative negligence in an automobile accident case.)