Q: Are turn signals required in parking lots?

A: Yes, they’re not required by law, but they are a requirement for human decency.

It’s like golf. When a golfer hits a ball, and it goes an unintended direction, they’re supposed to yell “Fore!” and even point in the direction of their errant shot, to warn other golfers a ball is headed their way. Police aren’t waiting around with a ticket book to issue an infraction to anyone who fails to yell fore, but golfers give the warning because it’s the right thing to do.

Turn signals are such a useful tool that it’s almost strange we even need a law to get people to use them. They’re the only practical way to let other road users know where you intend to go. When other drivers can better anticipate where you’re headed, you’re less likely to collide. Turn signals are one of the few things in life that offer a clear upside, with no downsides. Why wouldn’t you want to use them?

But you probably want to know about the law. Nearly all of the traffic laws in Washington “refer exclusively to the operation of vehicles upon highways.” A highway, as defined by law, means, “the entire width between the boundary lines of every way publicly maintained when any part thereof is open to the use of the public for purposes of vehicular travel.” Or more simply, if it is open to the public, built for travel, and paid for with tax dollars, it’s a highway. That includes a lot of places (even ferries), but it doesn’t include parking lots.

There are exceptions for the big stuff; impaired driving, reckless driving, negligent driving, vehicular homicide, vehicular assault and hit-and-run collisions can all be enforced on private property. And that makes sense; no one should get a free pass to do something potentially disastrous with their car, just because they’re not on a public roadway.

As drivers, we’re piloting multi-ton projectiles on a network filled with other strangers and their projectiles. The system works because we have a shared set of agreed-upon rules on how to behave together. That builds trust, at least enough that most days we don’t even consider the possible risks of another driver failing to live up to the trust we’ve placed in them.

When we neglect to follow that shared set of rules, we compromise trust. To quote the wisdom of Frederick Douglass (out of context), “Trust is the foundation of society … and where there is no trust, there can be no society.” Will forgetting to use your turn signal cause the downfall of society? Probably not. But why risk it?

Setting aside the hyperbole, turn signals truly are a helpful communication tool while driving, whether you’re on a public road or looking for a parking spot. You won’t get a ticket for not using your turn signal in a parking lot, but do it anyway, for the good of humanity.

Doug Dahl writes a weekly column for this newspaper. He is with the state Traffic Safety Commission.