Roadside spraying FAQs


Why does the County spray roadside shoulders?

Roadside spraying is a routine maintenance activity. It's performed every year to keep vegetation from encroaching onto the roadway and/or to prevent proper stormwater drainage.

Which roads get shoulder spraying?

About 850 shoulder miles of spraying are included in the County's Road Maintenance Program.

When is spraying performed?

Mid-spring is the most effective time for roadside shoulder spraying. Spraying is generally performed at night when there is little or no wind and impacts to the traveling public are minimized.

Who performs this work?

The County contracts with a private contractor for roadside shoulder spraying. The contractor is selected through a competitive bid process.

What rules govern roadside spraying?

State and federal herbicide application rules must be followed. Additionally the County's contract requires that the products and application methods meet the County's Best Management Practices for Routine Road Maintenance, protecting the environment.

How is spraying conducted?

A large tanker truck with a spray bar drives along the road, spraying the road edge. The contract specifies that shoulder spraying will not exceed beyond 3 feet from the edge of the roadway. Roadside shoulders that are adequately maintained may not be sprayed.

What products are used?

Contractors use an approved mixture of Roundup Pro, Esplanade and Liberate. A special additive called a surfactant reduces unwanted drift by increasing droplet size.

Is it possible to opt out of spraying?

Citizens can submit a "No Spray" Program agreement if they don't want vegetation adjacent to their property sprayed. Signs are available for purchase from Operations and Maintenance.

For more information call (503) 846-ROAD (846-7623) or email