Reciprocal Traffic Mitigation Agreements, Forms & Information
Interlocal Agreements (Reciprocal Traffic Mitigation)
Snohomish County has Interlocal Agreements (ILA’s) with the Washington State Department of Transportation (WSDOT) and numerous cities related to mitigation of traffic impacts from new developments. The agreement with WSDOT provides for the mitigation of traffic impacts to state highways caused by traffic generated from new developments in the unincorporated county. The agreements with the cities are ‘reciprocal’ in that they provide for mitigation of impacts on city streets from county developments and mitigation of impacts on county roads from city developments. View links below to the interlocal agreements and supporting forms and documents.
Generic "Offer" Forms
Applicants use these forms to make the appropriate mitigation offers to the City or the County.
- Generic Offer Form for All Developments Inside Cities (PDF)
- Generic Offer Form for All Developments in the Unincorporated County (PDF)
Agreements, Forms & Information for Each Individual City
Arlington
- 1999 Agreement on Reciprocal Mitigation of Transportation Impacts (PDF)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
- Mitigation Zones (PDF)
- Future Connectors (PDF)
Bothell
- 2016 Agreement on Reciprocal Mitigation of Transportation Impacts (effective October 17, 2016) (PDF)
- County and City Development Traffic Percentage Influence Area Map (effective October 17, 2016; updated January 11, 2018) (PDF)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
- 2006 Agreement on Reciprocal Mitigation of Transportation Impacts (PDF) (Expired January 1, 2016. Developments submitted and subject to this agreement prior to January 1, 2016 are still subject to this agreement)
- County and City Development Traffic Percentage Influence Area Map (expired October *, 2016) (PDF)
Gold Bar
- 2003 Agreement concerning Annexation and Urban Development within the Gold Bar Urban Growth Area (PDF)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments
Granite Falls
- 2002 Agreement on Reciprocal Mitigation of Transportation Impacts (PDF)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
Marysville
- 1999 Agreement on Reciprocal Mitigation of Transportation Impacts (PDF)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
- Mitigation Zones (PDF)
- Proposed Road Connections (PDF)
Mill Creek
- 2019 Agreement (Effective February 20, 2019)
- 2016 Agreement (Expired December 31, 2015)
Monroe
- 2008 Master Annexation Agreement (PDF) (see Section 8 and Exhibit C for provisions pertaining to reciprocal traffic mitigation) (2 MBs)
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
Mukilteo
The original Agreement was amended effective August 7, 2019 and is now in effect until December 31, 2029. The amendment modified Sub-sections 3.5, 3.6, 4.5, 4.6, and Section XII. All other sections of the original Agreement are still in effect.
Effective August 3, 2009
- 2009 Agreement (PDF) titled "Interlocal Agreement between Snohomish County and the City of Mukilteo regarding Inter jurisdictional Review and Mitigation for Development Impacts on Their Respective Transportation Infrastructure"
- City Traffic Study Requirements for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
Stanwood
- 2004 Agreement (PDF) concerning Annexation and Urban Development within the Stanwood Urban Growth Area
- City Traffic Study Requirements for County Developments (PDF)
- Mitigation Zones With Percentages for County Developments (PDF)
- County Traffic Study Requirements for City Developments (PDF)
Sultan
Washington State Department of Transportation
- 1997 Agreement 9709190470 (PDF) relating to Policies and Procedures for Interjurisdictional Review of Land Development Impacts related to Transportation, and for Reciprocal Impact Mitigation for Interjurisdictional Transportation System Impacts
- 2000 Amendment No. 1 to Agreement 9709190470 (PDF)
- 2003 Amendment No. 2 to Agreement 9709190470 (PDF)
- 2004 Amendment No. 3 to Agreement 9709190470 (PDF)
- 2009 Amendment No. 4 to Agreement 9709190470 effective 2/20/2010 (PDF)
- Previous WSDOT Exhibit C prior to 2/20/2010 (PDF)
- Current WSDOT Exhibit C Effective 2/20/2010 (PDF)
- Mitigation Offer Form (Long Version) (PDF)
- Mitigation Offer Form (Short Version) (PDF)
- Traffic Impact Analysis Checklist Section One (PDF)
- Traffic Impact Analysis Checklist Section Two
Traffic Study Tools & Information for Developers & Traffic Consultants
To read these files you’ll need Adobe Reader installed on your computer.