The Washington State Transportation Commission is seeking input on the commission’s plan to raise toll rates for the Tacoma Narrows Bridge.

The commission has proposed a 50-cent increase in 2015 and an additional 50-cent increase in 2016.

If approved, tolls would rise in July 2015 and July 2016. Cash tolls would rise to $6 this year (and to $5 for Good To Go! accounts and $7 for pay-by-mail customers).

Comments will be accepted through Wednesday, May 20.

Three meetings will also be held on the rate proposal; one online, and two in Gig Harbor.

The online meeting is 6 to 8 p.m., Wednesday, April 15. Following a presentation on the rate proposal and project, commissioners will answer questions and take comments through a moderated online chat format. Get details on how to participate on the WSTC website at www.wstc.wa.gov.

Public input will also be taken from 6 to 8 p.m., Wednesday, April 22, and 6 to 8 p.m. Wednesday, May 20 at meetings at the Gig Harbor Civic Center, 3510 Grandview St.

The commission is expected to vote on the toll proposal at the May 20 meeting.

In addition to the public meetings, comments can be submitted until May 20 via email at transc@wstc.wa.gov (indicate “TNB Rates” in the subject line) and on the commission website, under “contact us,” at http://wstc.wa.gov/ContactUs/feedback.htm.

Comments can also be submitted in writing to: Washington State Transportation Commission, PO Box 47308, Olympia, WA 98504-7308.

Officials note that 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 $54 million in 2015 to $73 million in 2019, officials said.