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Vegetation Maintenance Cost Comparison

There are currently six counties in Western Washington that maintain their road systems without the use of herbicides. WSDOT developed a comparison of cost and results between roadside maintenance practices on these county roads and those on state highways within the counties. The findings show that in order to preserve the same level of service WSDOT maintenance currently delivers, without the use of herbicides, the overall cost of roadside vegetation management would be close to double.

A Comparison of Roadside Maintenance Practices - Impacts of Herbicide use on Cost and Results (pdf 2 mb)

Most of the cost increase incurred when looking at eliminating herbicide use comes from maintenance changes at the road shoulder. In most cases WSDOT keeps this area vegetation free. In the six counties that don't use herbicides, grass is allowed to grow up to the edge of pavement. Further research will be conducted in the coming years for road shoulder maintenance in areas throughout the state.

The information in this report is now being checked against information gathered through actual field trials and part of ongoing research into alternative methods for maintenance of vegetation at the edge of pavement.

For more information, contact Ray Willard at (360) 705-7865, or e-mail