Q: Horns are supposed to be safety equipment, right? When everyone honks their horn locking their cars, is this misuse of safety equipment? By law, should car manufacturers be using a different sound? When I hear a horn now, I just figure it’s somebody parking their car.

A: You’re so close to being right. Yes, a horn is intended to give an audible warning to other drivers “to ensure safe operation.” Law states that drivers “shall not otherwise use such horn when upon a highway.” Those last four words are what you’re missing.

When you’re on the road, your horn is to be used only as a warning device. If your horn were to make a door-lock-chirp sound while driving, that would be a violation. Once you’re parked though, the limits on how you can use your horn no longer apply. Law even gives permission to use the horn as part of the vehicle’s alarm system.

On a related note, while it’s not illegal to use your horn as your alarm, it is illegal to use your alarm as a horn. Law permits what you’d like to see as a rule – alarms that sound different from the horn. However, that non-horn sound is not allowed to be used as “an ordinary warning signal.” It’s also not legal to use a siren for your car alarm. As you would expect, sirens are only allowed on emergency vehicles.

You’ve implied that car alarms are annoying, and I won’t argue with that. There’s also speculation that they’re ineffective. Respectable journals put the false alarm rate at around 95%. Car alarms are also part of the growing problem of noise pollution. But none of those concerns are traffic safety issues, and I’m out of my depth on those topics except to say to the people whose horns chirp when they lock their cars, you know you can turn off the beep, right?

Instead, I’m going to respond to your last statement. If you’re driving through an intersection and you hear a horn blaring, I bet you don’t “figure it’s somebody parking their car.” We assess what a horn means based on the context we hear it in.

That goes beyond horns; context plays a partner role with traffic law. Good drivers continuously monitor their environment and make decisions based on what they see and hear. Take a neighborhood with a 25 mph speed limit; sometimes it might be fine to drive at that speed, but if you see kids playing ball in a yard you’ll slow down so you have more time to respond to a stray pitch and the inevitable kid chasing it. Or in a location with high pedestrian traffic, you might choose not to make a right turn at a red light, even if it’s allowed.

Safe driving goes beyond the law, and includes responding to the context you’re in.

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