King County Road Services - Frequently-asked questions

Concurrency means that transportation facilities must be available to carry the traffic of a proposed development at County level of service standards, or else the proposed development cannot be approved. If standards are not met at the time you apply for development ("concurrent" with your application), the County can approve development only if financial commitments for improvements are made that will achieve the standards no later than 6 years after the development is approved. These commitments may be made by the County in its Capital Improvement Program, or by agreement between the County and the developer.

Concurrency is determined by adding the traffic from the proposed development to the traffic already on the roads and then calculating the projected level of service. This is then compared to the County's standard. If the projected level of service is as good as, or better than the standard, the development passes the concurrency test and the applicant will be issued a Concurrency Certificate. If the projected level of service is worse than the standard, the development fails the concurrency test and no Concurrency Certificate will be issued.

This system provides for the requirement that transportation system improvements be made concurrently with the completion of development.  Call 206-296-8764 for more information.

Unincorporated King County has been divided into about 562 concurrency zones, and each zone has the standard of the Transportation Service Area in which it is located. The standard for your development will be the standard for the Service Area in which your proposed development is located as set by the Comprehensive Plan and in KCC 14.70.220.

You specify the uses and size of the proposed development in your application for the Certificate of Concurrency. You may specify up to, but not more than, the maximum allowable density allowed by zoning and land use regulations.

You will receive a Certificate of Concurrency and the County enters the reservation in its concurrency records so that the concurrency cannot be given to anyone else. The Certificate must be a part of the development permit application to the Department of Development and Environmental Services (DDES).

If an application for a residential proposal is denied, you will receive a denial letter. There is no administrative appeal of the Department's final decision of denial.

If an application for a non-residential proposal is denied, you will be issued a letter of denial, explaining three options:

1. You may request in writing a 90 day review period. During this period you may meet with the department to review the concurrency analysis and possible mitigation measures. Any mitigation must achieve the County's level of service standard. The 90 day period must be requested no later than 10 days after receipt of the notification of denial.
2. You can appeal the decision to the Department's director or the director's designee within 10 days of receipt of notification denial or within 10 days after the expiration of the 90 day period. The appeal will be considered by the Hearing Examiner. Grounds for appeal are:
   • technical error
   • applicant's alternative data or traffic mitigation plan was inadequately considered by the department
   • conditions for certificate of concurrency are not relevant to concurrency
   • denial was arbitrary and capricious.

3. You can accept the test results and take no further action. You will not be able to obtain permits for the proposed development (but you may resubmit your application at a later date when improvements may have occurred to County roads to increase capacity).

You have 365 days from the date on the certificate of concurrency to file your development application with DDES. If your development approval does not have an expiration date, the Certificate will be good for 5 years from the approval date.

No. Concurrency is the pre-application stage in the permit process. A certificate allows you to move forward in filing for the development permit. You will still need to meet all requirements and regulations associated with filing for a development permit.

Any development capacity that you do not use will be reallocated by the county to other developments.

No. Certificates of concurrency run with the land, and can be transferred only to subsequent owners or developers of the land. Concurrency cannot be transferred to other parcels (because they may be in different concurrency zones or different land uses). Subdivision of a certificate among multiple tracts or parcels in the same development is subject to County approval.

Anyone who intends to apply for a development permit in unincorporated King County, including short plats in the rural growth area.

No, every project is required to have a concurrency review. Single family building permits and urban short plats can apply directly to the Department of Development and Environmental Services (DDES) for their concurrency review.

There is no fee for a concurrency analysis.

Yes. The Mitigation Payment System (MPS) requires that you pay for road improvement needs based on the traffic impact of your development. For MPS information call Jeff Lee at (206) 263-4759. The County may also require that you pay for traffic related improvements in the vicinity of your development. For more information contact the Road Services Division at (206) 296-6596.

For more information about concurrency, visit the concurrency management Web site or contact:

Jeff Lee
King County Department of Transportation
Road Services Division
201 South Jackson Street, MS KSC-TR-0317
Seattle, WA 98104-3856
Phone: 206-263-4759
Fax: 206-296-0566