Bridge toll rate changes are coming.

As of today daily commuter with a Good to Go Pass pays $1,000 per year for tolls on the Tacoma Narrows Bridge.

The Washington State Transportation Commission has proposed a toll-rate increase of 25 cents beginning July 1. The new tolls are: Good to Go $4.25, toll booth payments $5.25 and pay-by-mail $6.25. This amount increases commuters’ payments by about $5 per month.

A 25-cent increase for July 1, 2014 also has been proposed.

During a recent toll meeting, WSDOT’s Dan O’Neill said “if rates are kept low this year, a bigger bump will occur next year.”

According to WSDOT’s “TNB Toll Rate Setting” revised in December 2013, tolls on the Tacoma Narrows Bridge must cover costs to make debt service payments on construction bonds, operate and maintain the new bridge (but not the old one), operate and maintain toll collection, make necessary repairs and restoration to the new bridge, and purchase insurance in case something happens that takes the bridge out of service (but not the lack of vehicles crossing).

WSDOT said toll rates must change because the original finance plan that funded TNB construction included 10 separate bonds that required low debt service (repayment) in early years after construction that increase rapidly for the first 10 years and less rapidly after that with more interest paid each year.

The plan assumed the average toll rates would begin at $3 when the bridge opened, increasing $1 every three years until reaching a maximum of $6.

To date, WSDOT data show due to reduced costs and better than projected traffic in the early years, toll rates have remained lower than originally projected.

The new bridge opened in 2007 with tolls of $1.75 for Good to Go and $2 for cash. In July 2010, the toll increased to $2.75 for Good to Go and $4 for cash; the original plan was for $4 for all tolls.

In July 2012, the toll-rate increased to $4 for Good to Go, $5 for cash and $6 for pay-by-mail, although the original plan called for the toll to be $5 for all pay plans. According to the original finance plan, the toll will eventually be $6 for Good to Go.