This 103-year-old Pierce County bridge is deteriorating. It has a new weight limit

If you have plans to cross the Carbon River Bridge just south of Carbonado, you may want to check your vehicle’s weight first.

The state Department of Transportation (WSDOT) recently placed weight restrictions on the bridge on state Route 165. Anything over 8 tons or 16,000 pounds can no longer cross the bridge, according to a July 31 blog post from WSDOT.

When asked what type of vehicles the weight limit affects, WSDOT spokesperson Cara Mitchell wrote in an email to The News Tribune Aug. 12 that it depends on the total weight of the vehicle plus anything inside of it.

For example, a 2024 Toyota Corolla LE can weigh 2,955 pounds, according to Toyota . A 2025 Ford Explorer SUV can weigh 4,345 pounds, according to Ford . An Alpine fifth wheel RV can weigh between 12,391 to 14,577 pounds, according to Keystone RV Co . A fire engine can weigh 20,000 to 40,000 pounds, according to the International Fire & Safety Journal .

Motorists can find a vehicle’s weight in the vehicle’s manual, inside the driver’s side front door or on their vehicle registration. The state also has fee-based weigh stations , 13 of which are in Pierce County.

RVs come in many different sizes, Mitchell said. Same with first responder vehicles.

“We are in communication with East Pierce Fire and Rescue and Buckley Fire Department on access for the emergency detour route that we are obtaining permits for,” Mitchell wrote in the email.

When asked if fire engines have a way to respond on the other side of the bridge or if they are out of luck until permits come through, Mitchell said East Pierce Fire and Buckley Fire have access to gates on a proposed detour route.

Asked how the weight limit will be enforced, Mitchell said: “WSDOT is not an enforcement agency,” and referred The News Tribune to a state law that outlines penalties for violating weight restrictions . The law explains how the size of the penalty depends on whether it’s a first offense and how many pounds a vehicle is over the limit.

This is the third restriction WSDOT has placed on the bridge since 2009.

“In April 2009, loads exceeding 12 feet wide were prohibited,” Mitchell said.

Then in May 2013, WSDOT restricted commercial vehicles from using the bridge.

Advanced deterioration

The bridge is 103 years old, and it is 494 feet long. This spring, engineers noticed advanced deterioration of some parts of the bridge.

The bridge is made of steel and timber. Steel deteriorates when exposed to rain and snow. Water can rust steel and weaken it. WSDOT “combats” rust by painting over it, according to the blog post.

Last May, crews replaced aging wood bridge deck panels.

“Deferred preservation has been an ongoing issue for years. Prior budgets passed by the Legislature have not provided funding to replace or make repairs to the bridge … Without more investment in preservation, we will continue to see more bridges weight listed, longer detours (where applicable) in place and highways with ‘rough road ahead’ signs,” WSDOT wrote in the blog post.

When asked how much money it would take to fix the bridge to increase the weight limit again, Mitchell said WSDOT’s engineers are looking at those costs now, and that they do not have a cost estimate at the moment.

Mitchell said vehicles can still access areas south of the bridge as long as they are less than 8 tons or 16,000 pounds. The weight restriction helps extend the bridge’s life, she said.

“WSDOT is actively pursuing permits to create an emergency access route for property owners and emergency vehicles over the 8-ton weight limit. The permits we are pursuing ... are for one year. This gives time to decide what the path forward is,” Mitchell wrote in the email.

A bridge typically lasts 75 years, according to the blog post. In Washington, the average state-owned vehicle bridge is 51 years old. The Carbon River Bridge was built in 1921, and it cost $500,000.

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