Transportation Development Tax / TDT

Updated:  April 24, 2014

Transportation Development Tax 
Tax on new development, dedicated to transportation improvements.


On Tuesday November 4, 2008 the citizens of Washington County approved Measure No. 34-164, the Transportation Development Tax (TDT). The TDT replaced the previous tax, known as the Traffic Impact Fee (TIF), passed county-wide in 1990. The TDT went into effect on July 1, 2009, increasing the previous TIF rates as well as updating and clarifying various procedures. Once fully phased-in, the TDT will essentially double the rates developers pay for the impact new development has on the transportation system. The TDT is levied countywide including within the Cities.

The TDT has been thoroughly reviewed by the Washington County Coordinating Committee (WCCC).  The TDT is based on the estimated traffic generated by each type of development. All revenue is dedicated to transportation capital improvements designed to accommodate growth. Eligible projects are on major roads, including sidewalks and bike lanes, as well as transit capital projects (such as bus shelters).

The TDT is not a property tax.   The TDT is imposed on all new development in Washington County,  except for temporary uses  that will exist for no more than  90 days, and remodeling or replacement of existing  uses, except to the extent that remodel or replacement of a use increases its capacity to intensify demands on the transportation system.

The  TDT  is collected prior to the issuance of a building permit; or in cases where no building permit is require (such as for golf courses  or parks ), prior to final approval of development application.  Options exist, however, for payment of the tax over time, or in certain cases, deferral of payment until occupancy.  Credit toward the TDT may also be approved for constructing eligible transportation improvements.

The TDT rates were scheduled to be phased over a 4-year time period. Because of the recession, the Board of County Commissioners adopted an Ordinance (A-Engrossed No 746) which delayed the final step-increase of the TDT rate phase-in schedule to June 30, 2015. This delay was reviewed and continued in the spring of 2013 and will be reviewed again in the spring of 2014. The final step increase is currently scheduled to occur on July 1, 2015 unless the Board takes further action before that time.


Temporary Discount for Change of Use

Effective July 19, 2012, applicants changing the use of an existing building may be eligible for a TDT discount as high as 75%. At the request of the Washington County Coordinating Committee, the Board of County Commissioners considered and approved this temporary discount on June 19, 2012 under Ordinance 751. Discount eligibility is limited to buildings at least three years old that are changing to certain commercial, industrial or office uses. Discounts are applied to the first 5,000 square feet of floor area, and are calculated at 50% for buildings three years or older, and 75% for buildings 20 years or older. The discount expires on June 30, 2015. See Ordinance 751 or contact county LUT staff for more details. 

TDT Forms 


TDT Code Language & Rules


Manuals and Reports

TDT Annual Report 2012-2013

TDT Annual Report 2011-2012

TDT Annual Report 2010-2011 

TDT Annual Report 2009-2010

North Bethany TSDC Annual Report 2011-2012 

Procedures Manual 


TDT Election Materials

Ballot Title

Explanatory Statement

Election Results

Newsletter/Frequently Asked Questions


Adopting Ordinances

Official adopted version of A-Engrossed Ord. 691

Official adopted version of Ord. 729

Official adopted version of Ord.741

Official adopted version of A-Engrossed Ord. 746

Official adopted version of Ord. 751