If you're turning left from a left-turn only lane, do you really need to activate your turn signal, even if there are no drivers or pedestrians in the area.

Yes, said the Washington Supreme Court in a unanimous opinion today.

In State v. Brown, the Court held Washington drivers must use their turn signals every time they turn left or change lanes.  

The facts in State v. Brown

In March 2015, a Washington state patrol officer saw David Brown traveling in the center lane of a main roadway in Kennewick at 10:15 pm.  Brown activated his turn signal, moved into the dedicated left-hand turn lane, at which point his turn signal flipped off.  There was no other traffic or pedestrians in the area.

Brown stopped at the red traffic light, and when the light turned green, he turned left, but Brown didn't re-activate his turned signal.  The officer stopped him and after further investigation arrested Brown for DUI. 

Washington drivers must use their turn signals all the time

In State v. Brown, the Washington Supreme Court had to grapple with the meaning of RCW 46.61.305, the statute that contains the rules for turning left and using turn signals.

RCW 46.61.305 has two subsections. 

RCW 46.661.305(1) says that a driver cannot turn left without giving an “appropriate signal in the manner hereinafter provided” and you cannot turn left unless you can do it safely.

RCW 46.61.305(2) says that the use of turn signal “when required” has to be done “continuously” for at least 100 feet before turning. 

The Court of Appeals ruled that the statute only requires a turn signal when public safety is affected.  The phrase “when required” in RCW 46.61.305(2) really means “when required for public safety.”  Because no one else was in the area, therefore, Brown did not have to use a turn signal. 

The Washington Supreme Court disagreed.  The plain language of RCW 46.61.305(1) requires two things:  (1) safe movement; and (2) use of an appropriate signal.  RCW 46.61.305(2) lays out the manner in which drivers must use their turn signal (i.e. at least 100 feet before the turn).  It doesn't describe when a driver must use a turn signal. 

Brown's argument—that a turn signal is only required when public safety demands it—isn't a totally unreasonable reading of the statute, but it's not totally reasonable.  The main problem is that drivers may not necessarily know whether other drivers or pedestrians are in the area.  Washington is full of unprotected left hand turns and blind corner and strange intersections.  

“Leaving the decision to use a signal to the perception of individual drivers,” the Court wrote, “undermines the ultimate purpose of traffic laws: preventing accidents and encouraging highway safety.”