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Traffic Barriers - Safety is our top priority

Traffic barriers reduce the number of head-on, deadly and disabling collisions because fewer vehicles can cross the median. Driver concerns along with accident data are reviewed to make sure the right barrier is installed for each location. More information on this process can be found on our statewide cable median barrier project page.

Types of Highway Barrier 

In our state, we use three general types of barriers: cable, guardrail, and concrete. Each barrier type is designed to protect drivers, though they do so in different ways.

Cable Median Barrier


  • Flexes up to three feet
  • Allows drivers some control after impacts
  • Often used in areas with steep slopes
  • Also allows water to pass underneath

Concrete barrier

  • Little or no flexibility
  • Redirects drivers back into their lane or shoulder
  • Best in areas where there's traffic moving in opposite directions in close quarters, where there's no room for a median.

None of these barriers can protect every driver in every situation. WSDOT engineers strive to choose the best barrier for each highway location and consider many factors when deciding which type of barrier will be most effective. Deciding factors include:

  • amount of traffic
  • accident history
  • traffic speeds
  • curves (road geometry)
  • installation and maintenance cost
  • available median and shoulder space
  • grade and median slope
  • characteristics of each type of barrier
  • environmentally sensitive areas and drainage

Isn't concrete barrier the best choice?
Not always. It's often safer for a driver involved in an incident to run off the road onto a flat, grassy median or shoulder rather than hitting a concrete barrier. Unfortunately, the median or shoulder isn't always wide enough to safely stop if you run off the road.

Does WSDOT use any other safety features?
WSDOT uses several other safety features in conjunction with barrier:

  • rumble strips: help keep drivers alert if they veer out of their lane toward the shoulder or the median
  • enforcement: Washington State Patrol troopers help assure that drivers obey speed limits and other safety laws
  • speed limits: reduced speeds in some areas can save lives

What can drivers do?
Because barriers can't protect every driver in every situation, drivers should take steps to avoid collisions:

  • drive defensively
  • adjust your driving for weather and traffic conditions
    allow adequate following distance
  • never drive tired or under the influence of drugs or alcohol
  • make sure that your vehicle's safety equipment is well maintained

Cable median barrier