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Traffic Impact Analysis Guidelines

Development proposals that are subject to SEPA require a traffic impact analysis to determine transportation concurrency and to estimate traffic impacts and mitigation. Development proposals subject to SEPA exemptions listed in KMC 24.02.065 include

(a) The construction or location of any residential structures of 20 or fewer dwelling units (WAC 197-11-800(1));

(b) The construction of a barn, loafing shed, farm equipment storage building, produce storage or packing structure, or similar agricultural structure, covering 30,000 or fewer square feet, and to be used only by the property owner or his or her agent in the conduct of farming the property. This exemption shall not apply to feed lots (WAC 197-11-800(1));

(c) The construction of an office, school, commercial, recreational, service or storage building with 12,000 or fewer square feet of gross floor area, and with associated parking facilities designed for 40 or fewer automobiles (WAC 197-11-800(1));

(d) The construction of a parking lot designed for 40 or fewer automobiles not associated with a structure (WAC 197-11-800(1));

(e) Any fill or excavation of 500 or fewer cubic yards throughout the total lifetime of the fill or excavation and any excavation, fill or grading necessary for an exempt project in subsection (a), (b), (c), or (d) of this section (WAC 197-11-800(1)). (Ord. 4452 § 1 (Att. A) (part), 2014: Ord. 4361 § 1, 2012: Ord. 4150 § 2 (part), 2008)

To assist applicants in the preparation of the transportation concurrency and traffic impact analyses, the City has established Traffic Impact Analysis Guidelines (PDF 364KB). The goals of these guidelines are:

  • To assist in the determination of project compliance with transportation concurrency requirements;
  • To allow a thorough and complete review of potential traffic impacts; and
  • To ensure that review and mitigation of all proposals occur in a consistent and equitable manner.

The guidelines are intended to cover a wide variety of situations and do not include special requirements that may apply to a specific proposal. To be sure that a specific traffic analysis contains the proper information, please review these guidelines with staff from the Public Works Department or from the Planning and Building Department.

The following files have been prepared in Adobe Acrobat. You will need Adobe Acrobat Reader (a free program) to view or print PDF files.  Get Adobe Acrobat Reader.

Traffic Impact Analysis Guideline PhotoTIAG Guidelines Memorandum (PDF 364KB)
City of Kirkland TIAG Guidelines:
- Appendix A - Impact Fee Ordinance and Impact Fee Schedule (PDF 165kb)
- Appendix B - Concurrency Management
- Appendix C - Transportation Section of Comprehensive Plan
- Proportional Share Impact Calculation Worksheet (Microsoft Excel - 50kb | PDF - 22kb)

Traffic Concurrency Application
 (PDF - 197kb)

Concurrency Level of Service Update

City Council adopted a new Comprehensive Plan, including a new transportation element, along with companion revisions to Concurrency (Kirkland Municipal Code Title 25) on December 8. 2015. New concurrency methodology was effective January 1, 2016.  

Traffic concurrency levels of service standards, shown in the Traffic Impact Analysis Guidelines (TIAG) and in Appendix C of the TIAG, are being updated to reflect the newly adopted concurrency testing procedures as described below.

Illustration of Concurrency Testing Thresholds

KMC Section 25.10.020 (Procedures) (4) specifies when concurrency testing is required:

- Changes to the uses, densities, and intensities that create an additional impact of more than 10 person trips or that result in a total project impact of more than 40 person trips shall be subject to an additional concurrency test.  Changes to the uses, densities, and intensities that create a reduced impact do not require an additional concurrency test.

The KMC Section 25.10.030 (Test) (2) specifies the testing methodology:

- For roads, the concurrency test consists of comparing the existing person trip capacity to the estimated person trip generation of the development being tested.  The test is passed if the existing capacity is greater than the estimated person trip generation.

The current adopted concurrency standard is the existing person trip capacity.  The existing person trip capacity is a function of the amount of funded capacity improvement projects that are in the adopted transportation capital facility plan (CFP).  

Kirkland’s current trip capacity standard is 11,716 person trips.

Developments applying for concurrency shall be tested against the standard until person trip capacity is altered by revisions to the funded transportation CIP or to the transportation CFP.

Find out more information on
KMC Title 25.

Transportation Engineer Thang Nguyen, (425) 587-3869,

Public Works
123 5th Avenue, Kirkland WA 98033
T. 425-587-3800 | F. 425-587-3807
Mon-Fri, 8 a.m. to 5 p.m.

Operations & Maintenance
915 8th St, Kirkland WA 98033
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