You are allowed one every 7 years or so. Costs about $200.00. If you have no other offenses in 1 year time the matter will be dismissed. You have to contest the ticket and then when you go to court ask for the deferral
When you receive an infraction citation (i.e. a "ticket") in Washington State, you have four options. First, pay the ticket at full face value to the clerk of court within 15 days from the date the ticket was issued. This can be a good option if you are busy, or from out of state, or if you have neither the time nor the motivation to fight the ticket in any way.
Second, you can request a mitigation review. This allows the court to take into consideration your driving record and any information you may have to offer about the situation which tends to lessen your guilt but not excuse it. Most courts require you to appear at a mitigation hearing and at least ask for a reduction of the fine in person. If your driving record is not too good, you can be denied any mitigation. Some courts also allow you to submit a written mitigation letter in lieu of actually appearing in court.
Third, you can ask for a contested infraction hearing to fight the ticket entirely. This hearing actually forces the state or city to prove the allegation against you. In the courts I work in, the prosecutor are greatly stepping up their efforts to win more and more of these hearings because most have tight budgets and most want money for their court.
As far as a deferred goes, this is your 4th option, and it's an option only if you request a contested or a mitigation hearing. Under state law, you can petition for a "deferred findings" on one moving violation and one non-moving violation every seven years. If the deferred is granted, you'll have to pay a deferral fee to the court, and you will have to go the next 12 months without receiving any more tickets.
After the 12 months is up, the court dismisses your ticket, and during the 12-month period, the ticket is NOT reported to your insurance company. But if you mess up and get another ticket, the deferral gets cancelled, and you receive a notice in the mail from the court clerk demanding the full face amount of the fine on the ticket, and if you do not pay it, they will suspend your license.
Courts can charge a lot of a deferral these days. A few years ago, the fees were typically $50 per ticket, but some court I have dealt with, now want more than the face amount of the ticket! I saw one court the other day that wanted $300 to grant a deferred findings on a $142 ticket!