OLYMPIA — The Washington State Transportation Commission on May 20 voted unanimously to increase the Tacoma Narrows Bridge toll rates, at its final hearing in Gig Harbor. It adopted a toll-rate increase of 25-cents in 2013, with an additional 25-cent increase in 2014, to take effect on July 1 each year.

The commission gathered and considered written comments on the proposed rate increase during the past two months and held two public meetings in Gig Harbor to allow for public testimony.

The new toll rates effective July 1, 2013 are:

• $4.25 for Good To Go! pass

• $5.25 cash

• $6.25 Pay By Mail

The commission is required by law to set toll rates for the Tacoma Narrows Bridge in an amount that is sufficient to pay the debt for the bridge, as well as to pay costs related to maintenance, preservation and operations of the bridge.

The bridge was financed with an escalating debt structure to minimize the initial toll rates and impact on bridge users. Debt payments started out low when the bridge opened to traffic in 2007 and are now rising steeply, requiring additional toll revenue each year to pay the escalating obligation. Over the next four fiscal years, debt service payments grow from $45 million in 2013 to $70 million in 2017.

The commission evaluates several factors during the toll-setting process, including bridge expenses that are paid for by toll revenue, trends in traffic volumes, the schedule for bond payments, ending balances in the toll revenue account, the rate recommendations from the governor-appointed Tacoma Narrows Bridge Citizen Advisory Committee and public input.