It is not enough to show that a defendant engaged in negligent or careless conduct. To recover in a personal injury case, you must prove not just negligence, but also that this negligence was the legal cause of your injuries. Legal cause is shown if the negligence was a substantial factor in producing the harm. An act is not considered a substantial factor in producing the harm if other factors actually caused the harm and the defendant’s act was harmless until acted upon by those other factors. The law in your state may vary in some degree, but essentially that is the way causation works.
To help illustrate legal causation, look at the following example in which one of the defendants claimed that his acts were not the legal cause for the accident.
Example: Sara was driving along the freeway. A tow truck ahead of her dropped a tow dolly on the road. The dolly was negligently fastened to the tow truck. Sara was able to bring her vehicle to a halt without striking the dolly. Unfortunately, her vehicle was then struck in the rear by another vehicle.
The lawyer for the tow truck company claimed that his client’s negligence was not a substantial factor in producing the harm. He claimed that, but for the unsafe conduct of the striking motorist, the negligent fastening of the tow dolly was quite harmless.
The judge agreed, as Sara was able to stop without hitting the dolly. Even though the tow truck driver’s actions were negligent, and even though that negligence led directly to Sara’s severe injuries, he had no legal responsibility whatsoever. The full brunt of the liability fell upon the striking motorist.