The Snohomish County Road Maintenance Division is responsible for approximately 1,556 total centerline miles of County maintained streets and roads across the county. In order to address resource constraints, and dispatch available resources where they are most needed during a major event, specific plowing and/or sanding routes are prioritized based on traffic volume (such as major arterial routes first), transit and school bus routes, terrain, and institutional knowledge of historical problem areas.

In the map at right, the following colors indicate the priority for snow and ice removal:

Color	Priority
Red	Primary
Yellow	Secondary
Blue	Tertiary

Additional information can be found in this document on the Snohomish County Website.