Figuring out who is at fault in a traffic accident is a matter of deciding who was careless. For vehicle accidents, there is a set of official written rules telling people how they are supposed to drive and providing guidelines that can help you measure liability. These rules of the road are the traffic laws that everyone must learn to pass the driver's license test. Complete rules are contained in each state's vehicle code, and they apply not only to automobiles but also to motorcycles, bicycles, and pedestrians.
Sometimes a violation of one of these traffic rules is obvious and was clearly the cause of an accident. Let's take a look at some examples.
Example 1: Bob drives through a stop sign and hits Mary's car. Going through a stop sign is an obvious violation that leads directly to a collision with someone coming through an intersection in a cross direction.
Example 2: Juanita does not look carefully and moves from the left lane to the right. Another car, driven by Arlene, is already in the right lane. Arlene swerves to avoid Juanita and hits a parked car. The accident was clearly caused by Juanita's traffic violation—her unsafe lane change—and is obviously Juanita's fault, even though her car never actually hit Arlene's car.
In other situations, whether or not there was a violation will be less obvious.
For example, Arnie merges onto a freeway. Ed does not give him room to enter, and Arnie's car strikes the side of Ed's car. A little research reveals that the rule in the state where the accident occurred is that the entering driver must give way to the driver who is already in traffic. Arnie was probably at fault.
In some cases, there may have been a traffic violation that had no part in causing the accident and therefore should not affect who is liable.
For example, Beatrice failed to signal when she made a right turn; Chain-Fa ran through a stop sign and plowed into her. Obviously, Chain-Fa's violation led directly to the accident. If he had stopped, he would not have hit Bea. But Bea's violation probably had nothing to do with the accident. Because Chain-Fa would have hit her whether she had gone straight or turned, signaling would not have prevented the accident.
It is sometimes difficult to say that one particular act caused an accident. This is especially true if what you claim the other driver did seems unimportant. But if you can show that the other driver made several minor driving errors or committed several minor traffic violations, then you can argue that the combination of those actions caused the accident.
Example: Lana was driving in the right-hand lane when John changed from the left lane to the right and ran into her. In the police report, John says he had already moved into the lane before the collision and that Lana was not paying attention.
This is the kind of case where it is often difficult to show who was most at fault, and an insurance settlement for Lana might be lower because of what appears to be her comparative negligence. That is, it seems both people were at fault.
But if, through the police report or a witness, Lana can show that John was driving over the speed limit, failed to signal a lane change, changed lanes too abruptly, or committed some other driving violation, in combination with Lana's claim that he did not give her the right of way, Lana's argument for liability could be stronger.
To learn more about how to prove fault for a car accident, and what to expect at every step in your case, get How to Win Your Personal Injury Claim by Joseph L. Matthews (Nolo). And if you're thinking about filing a lawsuit after a car accident, you may want to consider talking with a personal injury attorney to make sure that all your legal bases are covered and your rights are protected.