TRN-1.30 - Thresholds for Frontage Improvement and Dedication Requirements

I. Purpose

This rule implements Portland City Code (PCC) Section 17.88.020 by, in part, defining the two thresholds the Portland Bureau of Transportation (PBOT) uses to determine when frontage improvements or right-of-way dedication are required and by describing applicability and exemptions.
 

II. Definitions

Certain terms used in these rules are defined by PCC Section 17.88.010.
 

III. Regulatory Authority

The authority to develop this Administrative Rule is provided by PCC Section 3.12.040.
 

IV. Applicability

PCC Section 17.88.020 A. refers to two thresholds that are used by PBOT to determine whether development must provide standard frontage improvements or right-of-way dedication to accommodate those standard improvements: 
 

1. An increase in occupancy, which means an increase in daily trips generated by the site.
2. A significant alteration, which is defined in PCC Section 17.88.010. 

These thresholds apply to alterations, additions, and new construction.  Any damage caused to existing right-of-way improvements in the course of the development project must be repaired by the permit holder, regardless of exemption status or type of public works permit required. If the damaged existing right-of-way improvements do not comply with the minimum standards of the Americans with Disabilities Act (ADA) Public Right-of-Way Accessibility Guidelines (PROWAG), they must be repaired or replaced to at least those minimums, where practicable.

Regardless of exemption status, applicants must address all other City conditions of building permit and land use approval criteria such as driveway and sidewalk repair requirements under PCC Chapter 17.28, and the execution of waivers of remonstrance. An exemption determination will have no bearing on assessment of System Development Charges or whether a development meets Local Transportation Infrastructure Charge (LTIC) requirements as described in PCC Section 17.88.090 and TRN-1.26.

A building destroyed by a fire or other disaster is exempt from frontage improvement requirements if re-constructed within three years unless the replacement building would be larger than the destroyed one or intended for a different use.
 

V. Increase in Trips

1. Exemptions

   Proposed developments with the following characteristics are exempt from the increase in trips threshold as described below. The significant alterations threshold may still apply.

   1. Minimal Trip Increase 
      A proposed development is considered to create a “Minimal Trip Increase” when the total number of daily vehicle trips generated by the site will increase by: 

      • less than or equal to 15 percent AND
      • fewer than 250 trips  

      When both of the above are true, the development is not subject to the increase in trips threshold and associated improvement requirements. 

   2. Middle Housing Conversions 
      A development permit that adds one or two dwelling units to a site with existing dwelling units is not subject to the increase in trips threshold and associated improvement requirements if all of the following are true (see Figure 1):
      • the project, when combined with any existing units, will result in a total of three or fewer units on a site
      • the existing dwelling unit(s) are retained
      • the additional units each have an area of 1,199 square feet or less

Figure 1: Middle Housing Conversions

View full size image of examples of middle housing configurations

2. Threshold Calculation 

   PBOT determines an increase in trips by comparing the number of daily trips generated by the existing uses on a site to those generated by the proposed uses. The number of daily trips is calculated using the land use categories identified in TRN 9.06 (Transportation System Development Charges Administrative Procedures Guide). Daily trips are based on the current edition of the Trip Generation Manual published by the Institute of Transportation Engineers (ITE) at the time of building permit application. The trip rate for each land use category is identified in Appendix A.
   
   Existing (pre-development) trips are based on the last, legally-permitted uses on a site as determined by Portland Permitting & Development (PP&D). A site is considered vacant when no building has been present on the site in the past three years. Any development on a vacant site constitutes an increase in trips.
   
   When there is no land use category identified in TRN 9.06 that corresponds to an existing or proposed use, the closest category will be determined by PBOT based on the description of the use. An applicant may challenge PBOT’s determination with the submittal of an alternate trip rate study for review and approval by PBOT. PBOT may require an applicant to provide an alternate trip rate study in the absence of an applicable land use category.
   
   An alternate trip rate study must be prepared by a traffic engineer licensed in the state of Oregon. The study must include a minimum of three days of data collection at a minimum of three similar study sites in accordance with the methodology described in the current edition of the ITE Trip Generation Manual. A scope of work must be submitted for review and approval by PBOT prior to conducting the study. 

3. Improvement Requirements

   1. Frontage Improvements 
      Standard frontage improvements are required for a development that will result in an increase in trips.
   2. Property Dedication 
      Property dedication is required if necessary to accommodate standard frontage improvements.
      1. Property Dedication in Relation to Existing Structures 
         Property dedication is required to accommodate standard frontage improvements up to and around the façade of existing structures located within the required dedication area to the greatest extent possible (see Figure 2).
         
         For existing structures proposed to be retained within the required dedication area, PBOT may require modification or removal of private elements including, but not limited to, architectural features, landscape retaining walls, steps, fences, and decks. 

Figure 2: Property Dedication in Relation to Existing Structure

View full size image of shows new and old property line due to dedication in relation to an existing structure

3.  Corners 
   Except as otherwise provided in this section, corners must be constructed or reconstructed to achieve compliance with current federal ADA requirements and City standards at the time of building permit application. 
   
   A residential development that, when combined with any existing units, will result in a total of three or fewer units on the site is required to construct corners if: 

   1. improvements are required on both of the corner’s abutting frontages; or

   2. improvements are required on one frontage and the existing corner is incompatible with the improved sidewalk (e.g., the corner does not align with the pedestrian through zone of the improved sidewalk).  

New corner construction is not required if one or more of the frontages adjacent to the corner in question is eligible for, and the applicant pays, LTIC. Reconstruction of an existing corner may be required as described in this section. 

VI. Significant Alterations

Until January 1, 2029, the significant alterations threshold and improvements described in this section apply only to the following:

1. a.New construction of a building; and
2. b. Alterations or additions on a site with a Commercial-Institutional land use of K-12 School, University/College/Jr College, Hospital, or Park (see Appendix A).

1. Exemptions

   The following are exempt from the significant alterations threshold: 

   • A residential project on a site with three or fewer units.
   • Developments on LTIC-eligible properties. Significant alterations do not trigger payment of LTIC; refer to PCC 17.88.090 and TRN-1.26 for information on when payment of the LTIC is required.
   • Beginning January 1, 2026, a development described by Section 2(2) of House Bill 2658 passed by the legislature during the 2025 Regular Session.

2. Threshold Calculation

   Significant alterations are changes to property with a permit valuation equal to or greater than 35 percent of the assessed value of all improvements on the site. Mandatory improvements for fire, life safety and accessibility do not count toward the threshold. Repairs and maintenance to fix or mend a damaged or deteriorated structure or one of its constituent systems, or to prevent it from falling into a deteriorated condition, do not count toward the significant alteration threshold. The value of the alterations is based on the entire project, not individual building permits.
    

3. Improvement Requirements

   1. Frontage Improvements 
      
      Developments that meet the significant alteration threshold must construct frontage improvements to the extent feasible within the existing right-of-way.  
      
      If an improvement within the existing right-of-way cannot comply with the minimum clear width standards of the ADA, no improvements are required.  
       
   2. Property dedication 
      
      Property dedication is not required for a development that only meets the significant alterations threshold.  
       
   3. Corners 
      
      Corners must be constructed or reconstructed to achieve compliance with current federal ADA requirements and City standards at the time of building permit application.
       

VII.  Effective Date

This rule takes effect October 24, 2025.