How is Fault Determined in a Car Accident?

After the initial shock of a car accident, one question rises above all others and becomes the focus of everything that follows: Who was at fault? The answer to this question determines who is financially responsible for the medical bills, lost wages, and vehicle repairs that result from the crash.

Many people believe that fault is decided by the drivers arguing at the scene or is based on one single piece of evidence. In reality, determining legal fault (also known as “liability”) is a formal investigative process. It’s not about opinions; it’s about applying the law to a set of proven facts.

Insurance companies and lawyers investigate an accident to answer one key question: which driver acted negligently? Understanding how negligence is proven and what evidence is used is the key to understanding how fault is determined in Washington State.

Useful Information for You: In a Nutshell

• It’s Based on “Negligence”: Fault is legally determined by which driver failed to act with reasonable care, a concept known as negligence.
• Evidence is Everything: Fault is not decided by arguments, but by analyzing evidence like the police report, photos, witness statements, and vehicle damage.²
  
   
• Traffic Laws are Key: A driver who violates a traffic law (like speeding or running a red light) is often found to be negligent and, therefore, at fault.
• Washington Uses “Comparative Fault”: More than one driver can be found partially at fault.³ Under Washington law, your compensation is simply reduced by your percentage of fault.⁴
  
   
   
• The Insurance Company Makes the Initial Call: The insurance adjusters for each party will conduct their own investigation and make an initial determination of fault, which you have the right to dispute.⁵
  
   

The Legal Standard: Proving Negligence

For a driver to be held legally at fault for an accident, it must be proven that they were negligent. Negligence is a legal concept that means a person failed to exercise a reasonable level of care to prevent harming others.⁶ To prove negligence, four elements must be established:

1. Duty: Every driver on the road has a legal duty to operate their vehicle with reasonable care and obey all traffic laws. This is a given in any car accident case.
2. Breach: The driver breached, or violated, that duty.⁷ This is the core of determining fault. A breach can be an action (like speeding) or an inaction (like failing to yield the right-of-way).
   
    
3. Causation: The driver’s breach of duty must be the direct and proximate cause of the accident and your injuries.⁸
   
    
4. Damages: You must have suffered actual, compensable losses (like medical bills, vehicle damage, or lost wages) as a result of the accident.⁹
   
    

When an insurance adjuster or a jury looks at your case, they are essentially trying to determine who breached their duty of care.

The Evidence Used to Establish Fault

Fault is pieced together using all available evidence.¹⁰ No single piece is definitive, but together, they create a picture of what happened. The most important pieces of evidence include:

• The Police Report: While not always admissible in court, this is the most influential document during the insurance claims process. It contains the officer’s on-scene observations, a diagram of the crash, witness information, and notes on whether any traffic citations were issued.¹¹
  
   
• Photos and Videos: Your photos of the accident scene, vehicle damage, and surrounding area are powerful, unbiased evidence.¹² Dashcam footage is often the single most decisive piece of evidence.
  
   
• Witness Statements: Independent witnesses who have no stake in the outcome are highly credible. Their account of what happened can confirm your version of events.
• Vehicle Damage: The location and severity of the damage on the vehicles can help accident reconstruction experts determine the point of impact, speed, and angle of the collision.¹³
  
   
• Washington State Traffic Laws (RCWs): The “rules of the road” are the ultimate authority. For example, in a rear-end collision, there is a strong legal presumption that the rear driver breached their duty to follow at a safe distance.

The Impact of Comparative Fault

In many accidents, the fault isn’t 100% on one driver. What if someone turns left in front of you, but you were driving slightly over the speed limit? This is where Washington’s “pure comparative fault” rule comes in.

This rule allows fault to be shared. A jury or insurance adjuster will assign a percentage of fault to each driver involved.¹⁴ Your final compensation is then reduced by your percentage of fault.¹⁵ For example, if you are found 10% at fault, you can still recover 90% of your damages. This is why insurance companies will fight so hard to place even a small amount of blame on you—it directly saves them money.

Determining fault is a meticulous, evidence-based process.¹⁶ If you are in a situation where the other driver is disputing liability, you cannot win the argument with words alone. You must build a strong case based on facts.

If you’ve been in an accident in the Tacoma area and fault is being disputed, you need an advocate who knows how to gather and present evidence effectively. Search the Car Accident Lawyer Directory Tacoma to find and compare trusted local attorneys who can build a powerful case and fight to prove the other party’s negligence.

References

• Washington State Legislature – Title 46 RCW – Motor Vehicles:This contains the official “Rules of the Road” for Washington. A violation of one of these statutes is often the primary evidence of negligence.17

  https://app.leg.wa.gov/rcw/default.aspx?cite=46

• Washington State Pattern Jury Instructions (WPI 10.01) – Negligence—Adult—Definition:The official instruction that defines “negligence” for a jury in Washington State, which is the legal standard used to determine fault.

  https://www.courts.wa.gov/superiori/pattern_jury_instructions/WPI%2010.01%20Negligence%20-%20Adult%20-%20Definition.pdf

• Revised Code of Washington (RCW 4.22.005) – Effect of contributory fault:The official state law that establishes the “pure comparative fault” rule for shared-fault scenarios.

  https://app.leg.wa.gov/rcw/default.aspx?cite=4.22.005