Can You Mail in the Discovery Request USPS Certified with Return Signature

My question involves a traffic ticket from the state of: WA

I work all the time during the day, so getting into the courthouse is a big issue for me.

I was wondering if anyone can tell me if you can you mail in the Discovery Request USPS certified mail with return signature/receipt? Would this be the next most effective thing to serving the letter in person, and is this acceptable?

hoping for an answer quickly, thank you!

Can You Mail in the Discovery Request USPS Certified with Return Signature