Appendix Descriptions of the Transportation Needs Report

Appendix A-1 and Appendix A-2: Major Projects & Their Status

The road projects listed in Appendix A have been identified as major projects in the County’s 2015-2035 Transportation Element (TE) or in previous TNRs. Some of these major projects are included in the impact fee cost basis while others are not.

Appendix A-1 (PDF) shows the major projects included in the impact fee cost basis in 2011 and/or 2022 and their impact fee category. It also describes the fee categories and criteria used to select impact fee projects.

Appendix A-2 (PDF) shows all of the major projects and their current status (active or inactive). It lists both impact fee projects and major projects not included in the impact fee cost basis.

Appendix B: Cost Estimating Model

Costs for the major road widenings and new alignments are estimated using a model that takes basic data about each road project and applies various assumptions and unit costs. Appendix B (PDF) shows the current unit costs, major assumptions, and changes from the model’s previous iteration. Construction costs are based on Department of Public Works projects that have gone to bid and been constructed.

All construction improvements are assumed to follow the Snohomish County Engineering Design and Development Standards. Among other things, these standards designate the lane and shoulder widths required for arterial road configurations. The construction of curb, gutter, and sidewalk was assumed for arterials in the urban growth areas designated by the Snohomish County Comprehensive Plan. For the rural arterial segments, shoulder, and open ditch drainage construction were assumed.

Appendix C: Transportation Service Areas (TSAs)

The TNR establishes "Transportation Service Areas" (TSAs) for the purpose of calculating, imposing, and administering the traffic mitigation requirements of County regulations. In most cases, new developments are only required to establish concurrency and mitigate traffic impacts within the TSA in which they are located. Mitigation includes GMA-based impact fees, and may include mitigation for impacts on inadequate road conditions and adequate access and circulation provisions. Appendix C (PDF) provides detailed descriptions of the TSA boundaries and a map of their location.

Appendix D: Impact Fee Cost Basis

The TNR establishes the cost basis for Snohomish County’s GMA-based traffic impact fee. Appendices H, I and J provide information about the county’s impact fee program (PDF).

Appendix E-1: Information on Identified Major Improvements

Appendix E-1 (PDF) provides basic information on each currently identified major widening and new alignment. This appendix does not include major improvements that are "inactive" such as projects that have been completed or annexed. Projects are arranged alphabetically. Information includes the road name, project limits, project description, current and future lanes, TSA, and estimated ultimate right of way.

Appendix E-2: Information on Numbers of Lanes of Major Improvements

For each project in Appendix E-1 the number of current lanes, future travel lanes, and future turn lanes is listed in Appendix E-2 (PDF).

Appendix F: Identification of Improvements Needed to Support Planned Development

Appendix F (PDF) provides a description of the county’s traffic forecasting model that is used to identify the major widenings and new alignments needed to support new development.

Appendix G: Progress on Capacity Projects

Appendix G (PDF) evaluates the programming and construction of major road improvements to assess the progress being made towards implementing the TE.

Appendix H: Impact Fee Cost Basis Credits

This appendix (PDF) provides a description of the methodology used by the county to credit the impact fee cost basis for taxes paid by development and other public revenue sources. As a legal requirement, this credit is intended to avoid duplicative developer fees while ensuring the county does not rely solely on impact fees for cost basis projects.

Appendix I: Impact Fee Cost Basis Calculation Methodology

Appendix I (PDF) outlines the methodology behind how the county calculates transportation impact fees and provides an overview of the impact fee calculation process.

Appendix J: Snohomish County’s Impact Fee Program: Policy Overview

Appendix J (PDF) provides an overview of the policies and regulations governing impact fees in general, and Snohomish County’s program in particular.

Appendix K: Categories of Transportation Improvements & the Improvement Evaluation Process

Appendix K (PDF) provides an overview of the identification and evaluation of all categories of transportation improvements in the TNR. The appendix provides a table showing the different categories. The categories include the two categories of major road projects that are the focus of appendices A through J, as well as minor improvements, non motorized improvements, bridges, and drainage improvements. Appendix K also provides a description of the improvement evaluation process for each of the categories which provides a relative priority rating for each improvement.

Appendix L: Projects by Road Name

Appendix L (PDF) lists all of the currently identified road improvements for all categories of improvements. In this appendix the improvements are listed in alphabetical order by road name. This appendix is useful for determining whether or not improvements have been identified for any given road. If an improvement is found, the road number can be noted to look up the same improvement in Appendix M to see if it overlaps with any other improvements.

Appendix M: Projects by Road Number

Appendix M (PDF) also lists all of the currently identified road improvements for all categories of improvements. In this appendix the improvements are sorted by road number and milepost. This enables one to determine if other improvements are identified for the same or adjacent sections of the road.

Appendix N: Priority Pools by Improvement Category

Appendix N (PDF) shows priority pools for each category of improvement. In the “priority pools” all improvements with the same priority rating (high, medium, or low) are grouped together. Within the pools, the improvements are listed alphabetically. This is the final result of the improvement evaluation process. The purpose of the improvement evaluation process is to provide information that management and staff use in developing the Snohomish County six-year transportation improvement program (TIP). Programming of improvements, however, is not based solely on these priority ratings but the priority pools are one of the tools that management and staff use to make programming decisions.

Appendix O: Projects by Improvement Category

Appendix O (PDF) lists the projects and project information for each category of improvement. Projects are arranged alphabetically within categories.

Appendix P: Miscellaneous Documents

This appendix includes other miscellaneous documents to provide additional information including:

P-1. Overview of the TNR

A brief overview (PDF) of the main objectives and uses on the TNR.

P-2. Description of Appendices

Provides a brief description (PDF) of each appendix in the TNR.

P-3. Design Standard Assumptions Used for Major Projects

Summarizes the key design standard assumptions (PDF) used in scoping the major projects.

P-4. Drainage Needs Report (DNR) Projects Near Major Widenings & Non-Motorized Projects

The Drainage Needs Report (DNR) resulted from a major planning effort conducted by the Surface Water Management (SWM) division of Snohomish County Public Works. It included identification of surface water improvements throughout unincorporated Snohomish County. One of the objectives of DPW is to look for opportunities to coordinate transportation improvements with surface water improvements. This appendix identifies DNR projects that are located close to TNR projects in two categories, Major Projects, and Non Motorized Projects.

P-5. TNR Projects Located in Urban Centers

Snohomish County is working on planning strategies to develop two urban centers in unincorporated county. One is located near 128th street southwest and Interstate 5. The other is located near 164th street southwest and Interstate 5. This appendix (PDF) identifies those TNR projects, which lie within the proposed boundaries of the urban centers.