Who is at Fault in a Rear-End Accident in Washington?

In Washington state, fault in a rear-end accident is generally presumed to lie with the driver who rear-ended the vehicle in front. This presumption is based on the idea that all drivers must maintain a safe following distance and be able to stop safely to avoid a car accident or truck accident. However, there are certain circumstances where the leading driver may share or bear fault.

Sudden Stops

A sudden stop occurs when a driver abruptly halts their vehicle without a reasonable cause, giving the trailing driver insufficient time to react and stop safely.


  • A driver suddenly stops at a green light.
  • A driver slams on their brakes to avoid missing a turn.
  • A driver stops suddenly due to road rage or impatience with traffic flow.

Legal Implications

While the rear driver is typically presumed at fault, if it can be demonstrated that the leading driver’s sudden stop was unnecessary or unreasonable, the leading driver may share or bear fault. Evidence such as witness testimonies, traffic camera footage, or dashcam videos can prove that a sudden stop occurred and was unreasonable.

Non-Functioning Brake Lights

Brake lights signal drivers behind that the vehicle is slowing down or stopping. Non-functioning brake lights can lead to rear-end collisions as the trailing driver may not know the vehicle in front is stopping. Washington state law mandates that all vehicles must have operational brake lights.

Impact on Fault Determination

If the leading vehicle’s brake lights were not functioning, the rear driver might argue that they were not adequately warned of the stop, potentially shifting some or all fault to the leading driver. The condition of the brake lights can be documented through police reports, photographs taken at the scene, or vehicle inspections.

Illegal or Unsafe Lane Changes

These can cause the rear driver to accidentally hit the front driver because the rear driver does not have enough space or time to react.


  • Cutting Off: A driver cuts in front of another vehicle without sufficient space, causing the rear driver to brake suddenly.
  • No Signal: Changing lanes without signaling, leading to unexpected braking by the trailing driver.
  • Abrupt Maneuvering: Swerving into a lane abruptly due to impatience or to avoid traffic, causing a rear-end collision.

How This Affects Fault Allocation

If it’s proven that the leading driver made an unsafe lane change, they could be held partially or fully liable for the accident. Dashcam footage, traffic cameras, and witness statements are critical in proving an unsafe lane change.

Weather Conditions

Adverse weather can impact driving expectations in a few ways:

  • Reduced Visibility: Fog, rain, or snow can impair visibility, making it harder for drivers to see brake lights or signals.
  • Slippery Roads: Rain, ice, or snow can make roads slick, increasing stopping distances and making sudden stops more dangerous.
  • Driver Adjustments: Drivers are expected to adjust their driving according to weather conditions, such as maintaining a greater following distance and driving at a reduced speed.

Legal Implications

The rear driver must take extra precautions in adverse weather, maintaining a larger following distance and driving at a speed appropriate for the conditions. The leading driver must also drive safely and avoid sudden maneuvers that can cause accidents in poor weather.

In adverse weather, both drivers might share fault if it’s determined that they did not adjust their driving behavior to match the conditions. For instance, if the leading driver stops suddenly without a valid reason, and the rear driver is following too closely or speeding, both could be found partially at fault.

Let Brumley Law Help

Ultimately, fault determination can be complex and may involve traffic laws, witness statements, and accident reconstruction. Insurance companies and, if necessary, the courts will evaluate the specifics of each case to determine liability.

Contact Brumley Law Firm at (833) 832-2727 or through our online contact form to discuss your case and learn how our Kent rear-end accident attorneys can assist you.