Vertical Height Clearance
As an extra measure of precaution, the Bridge and Structures office of the Washington State Department of Transportation publishes bridge clearance heights up to 3 inches less than actual heights. For example, if the actual vertical clearance is 15 feet 3 inches, it may be listed in WSDOT’s Bridge List as 15 feet. It is the responsibility of the driver or freight hauler to consult the Bridge List or visit the oversize/overweight restrictions web page found on WSDOT’s website.
Bridge height signs
WSDOT posts height limit signs when the height of the bridge over the traveling lanes is less than 15 feet 3 inches. We are more conservative than national standards which require signs to be installed at 15 feet or under.
WSDOT publishes minimum and maximum bridge heights for each direction of travel on the WSDOT Commercial Vehicle Services website. The minimum and maximum measurements may fall inside or outside the traveling lanes, including shoulders. If an operator has an oversized load between the minimum and maximum measurements they are responsible for checking the vertical clearance prior to travel.