Police Traffic Stops in Washington State

There must be a valid reason to detain a citizen and it must be proved in court when challenged by the defense. All citizens in this country have the right to travel free of unjustified police interference. Traffic stops based upon a hunch and seemingly random police traffic stops of citizens are illegal. A DUI checkpoint (roadblock) is a random stop and is not permitted in Washington, although other states do allow the use of DUI checkpoints.

Typical drunk driving, such as weaving all over the road, is not the only reason people are stopped by police. Many people who are arrested for DUI are driving at night and were stopped for speeding, having a tail light out, driving with no lights on at night, or expired registration. Nobody denies that police would not make many of these traffic stops in the middle of the day but at night, it is a pretext to investigate a DUI.

What Do Police Officers Look for Prior to Stopping a Vehicle for DUI?

Police are trained to look for certain driving mannerisms that might indicate a chance that the driver is drunk, especially at night. Below is a list of suspicious driving mannerisms published by the National Highway Traffic Safety Administration and included in police DUI training that, police say, may indicate a driver at night is legally drunk and a traffic stop may be warranted:

Turning With Wide Radius 65%
Straddling Center or Lane Marker 65%
“Appearing” To Be Drunk (e.g., Slouching in the seat, Gesturing erratically or obscenely, Eye fixation, Tightly gripping the steering wheel Face close to the windshield, Drinking in the vehicle, Driver’s head protruding from vehicle) 60%
Weaving 60%
Driving on Other Than Designated Roadway 55%
Swerving 55%
Slow Speed (More Than 10 MPH Below Speed Limit) 50%
Stopping (Without Cause) in Traffic Lane 50%
Following Too Closely 50%
Drifting 50%
Tires on Center or Lane Marker 45%
Braking Erratically 45%
Driving Into Opposing or Crossing Traffic 45%
Signaling Inconsistent With Driving Actions 40%
Slow Response to Traffic Signals 40%
Stopping Inappropriately (Other Than in Traffic Lane) 35%
Turning Abruptly or Illegally 35%
Accelerating or Decelerating Rapidly 30%
Headlights Off 30%


Not all of these indications constitute violations of the law justifying the stop of a car. If a car is illegally stopped, generally speaking, anything discovered by a police officer after the stop is considered “tainted” evidence which cannot be used in court. The legality of the initial detention is often a critical and hard fought issue in a drunk driving case. Fighting the legality of a detention is important in every case. Additionally, on a broader scale, enforcing the Constitution is critical to protect the rights of all citizens.

Contact an Experienced Washington DUI Attorney

If you have been charged with a DUI, it is vital to have the representation of a skilled DUI attorney who can protect your rights. Offering capable counsel and dedicated advocacy, the Fox Law Firm PLLC has been helping clients throughout Washington obtain positive outcomes in their DUI cases since 1985. Contact Attorney Jon Fox for a free consultation by calling (425) 274-9190.