I live in Washington, which is a "Quasi-Duty-To-Inform" state with regards to concealed carry and permits. I do not have a concealed permit but I have a question about traffic stops and a properly secured and unloaded weapon, with the ammo separated from the firearm. During a traffic stop, do I have any duty to inform a police officer that I am transporting a legal firearm if I'm asked if I have any weapons? In my state, as I understand it, if I were carrying concealed, I would only be required to disclose that if asked by the officer. As far as I can tell, I have no duty to disclose an unloaded firearm being transported in a legal manner.

My concern is legal exposure. If I'm asked if I have a weapon and say no, I would be lying to the police. If I say yes, even with an explanation, would I be opening myself up to a possible Terry search? I'm not sure what would happen if I declined to answer. On paper, I have that right but I'm sure it wouldn't be received well. I'd like to believe that disclosing a legal firearm being transported legally wouldn't cause problems but I learned a long time ago that logic and reason aren't terribly useful in understanding the law many times.

I don't have anything to hide. I just have better things to do with my time than standing in the weeds while my vehicle is searched.

What do you think?

If a firearm is in the trunk, it may as well be at home. If I don't need to tell cops about guns I have at home, then I don't need to tell cops about guns in the trunk.

Look at page 8 here: https://handgunlaw.us/states/washington.pdf

Looks like it's illegal to have a loaded pistol in a vehicle unless you have a permit.
Since it's unlawful to have it loaded, they can't require you to disclose that (because that'd be a 5th Amendment violation).

Yours being unloaded, as you say, should be lawful. (I haven't found a law against it, anyway).
I didn't get far enough to see if there's another statute requiring disclosure.

In general, it's not illegal to lie to LE, just as it's not illegal for them to lie to you either.

Edit: Duty to Inform is page 9. There's no duty to inform, even for those with a permit.

(In my state, someone only has a duty to inform if they hold a permit.)