Bridge Guardrail Upgrades 2025

Regular guardrail is a metal safety barrier placed along roads or highways to stop cars from going off the road, especially in dangerous spots like sharp curves or steep drop-offs. It helps reduce crashes by keeping cars on the road.

Bridge guardrail, on the other hand, is specifically installed alongside bridges. Its purpose is similar, but it is often designed to be stronger or more protective because many bridges are elevated and may have higher risks if a vehicle goes over the side.

In short, bridge guardrail is a type of guardrail designed for the unique safety needs of bridges, while a general guardrail can be found along any part of a road.

Most travelers would never know they are going over a bridge because they cross streams and waterways that are narrow, or you might not be able to see the water from the road. One of the ways to tell if you are going over one of these bridges if you see guardrail on a part of the road that is straight and not curvy.
​

Guardrail is installed by drilling holes in the bridge deck or road and installing anchor bolts where the guardrail posts will be placed. Then steel posts which will hold up the rail are anchored to the bridge deck. These posts are spaced at regular intervals to provide structural support. After the posts are secured, the horizontal rails (usually steel or concrete) are attached to the posts. These rails form the protective barrier that prevents vehicles from falling off the bridge. Once the rails are in place, bolts and fasteners are tightened to ensure everything is secure. In some cases, additional reinforcement is added to make the rail stronger.
​

King County's contractors usually decide how they acquire guardrail materials. The county provides contractors with the necessary requirements.
​

King County uses a system to decide which bridge rails need to be upgraded first. This system looks at things like how weak the bridge is, how hard it is to upgrade, the type of rail on the bridge, and how the guardrail connects to the road.

We also look at the five-year crash history focused on run-off-road collisions. All traffic crash and collision data is reported and stored at the Washington State Transportation Data, GIS, and Modeling Office. This office is the source for the most complete and up-to-date information regarding any location in Washington State. It is the source we use for crash and collision information. For information on crashes on your roadway, submit your data request here.

Please report damage to guardrail to our 24/7 Road Helpline at 206-477-8100 or toll-free at 800-527-6237, or you may email maint.roads@kingcounty.gov.
​