MSTIP Bonding Cost-sharing Program

Transportation financing for high-growth residential areas

Overview: Innovative, Collaborative, and Proactive


Washington County, in partnership with the cities of Beaverton, Hillsboro, and Tigard, has developed a transportation finance program for four major residential growth areas:

  • North Bethany/Bonny Slope West (unincorporated Washington County)
  • South Hillsboro (City of Hillsboro)
  • South Cooper Mountain (City of Beaverton)
  • River Terrace (City of Tigard)

Forecasting: County roads cannot handle increased traffic


About 18,000 homes – and thousands of additional vehicles –are expected to result from these residential areas over the next 20 years. Many County roads will need upgrades to accommodate increased traffic and to improve safety for new and existing residents. The cost-sharing transportation fund will be used for a list of capacity and safety projects needed to serve the four areas.  (See Map).

Sharing the cost: Two-thirds County, one-third cities and development


Two-thirds of the $140 million cost of the identified capacity and safety road-improvement projects will be funded by Washington County; the remaining one-third will be funded by the cities and by development. The cost-sharing  is based on travel forecasting that estimates only one-third of travelers using the improved roads will result from the developments. The remaining traffic will be "regional travel"– trips that begin and end outside of the high-growth areas. This will improve county-wide mobility.

Funding projects: Getting ahead of the growth


  • The County will issue bonds to fund two-thirds of the project costs.
  • Incremental growth in revenue from the county-wide property tax-based Major Streets Transportation Improvement Program (MSTIP) will be used to pay back the bonds. Issuing bonds will allow improvements to be made proactively – before the deficient roadways become problematic.
  • Cities may use the Transportation Development Tax (TDT) and other development-based revenues to fund one-third of the project costs.
  • Additional partnerships, such as pipeline collocation opportunities with the Willamette Water Supply Program, will be pursued to obtain potential construction cost savings and to reduce traffic and community impacts.

Preserving funds: Other transportation needs still a high priority


The cost-sharing strategy preserves the existing MSTIP funding level of $35 million/year for improvements on other roadways throughout Washington County. By funding high-growth area road improvements through MSTIP-backed bonds, these high-growth projects will not compete with other transportation projects for MSTIP funds.