TRN-10.40 - Driveways – Operation and Location

A. Purpose

Ensure that driveway locations promote the safe and orderly flow of pedestrians,

bicycles, and vehicular traffic, preserve effective use of the curb zone, preserve or establish street trees, maximize opportunities for vegetated stormwater management, reduce conflicts with pedestrians and bicycles, and enhance the pedestrian environment.

B. Definitions

For the purposes of this rule, the following definitions will apply.

1. Driveway: a gravel or paved way for vehicular traffic extending from the roadway to the adjacent property line(s) for the purpose of providing access to legal parking or loading as provided under Portland City Code (PCC) Chapter 33.266.
2. Residential Driveway: a driveway serving only Residential Use Categories as defined by PCC Sections 33.920.100-110.
3. Industrial Driveway: a driveway serving only Industrial Use Categories as defined by PCC Sections 33.920.300-360.

4. Commercial Driveway: A driveway that is not solely a Residential Driveway or Industrial Driveway as defined herein.

    

C. Authority

Code authority for this rule can be found in PCC Section 17.28.110 Driveways-Permits and Conditions. Portland City Code Section 3.12.010 establishes the authority of the City Administrator to adopt administrative rules.

Design exceptions for driveway requirements are described in 17.28.110 F.

D. Driveway Operation and Location 

Driveway permits are allowed for the following uses: 

1. To access a legal parking space(s) as described in PCC Chapter 33.266 on abutting property; 
2. To access a legal loading space(s) as described in PCC Chapter 33.266 on abutting property; or 
3. To comply with fire code requirements.

1. Separation from Property Corner – Any portion of a driveway, excluding wings if required, must be separated from the corner of a lot where two streets intersect. See Table 1 for separation distance requirements. 

• Where these distances cannot be achieved, the applicant may seek a Design exception, but approved access may be restricted. 

• Driveways on corner lots with large radius property corners must not be placed within the curve. Narrow corner lots as referenced in Portland City Code Title 33 with a single house are exempt per Paragraph D.8., below.  

• At a "T" intersection of two Local Service Traffic streets where separation from the property corner is unachievable, a driveway may be sited at the top of the "T" aligned with the opposing street. The driveway cannot be in the legal crosswalk. A driveway design exception is not required for this configuration. See Figure 2. 

Table 1: Separation from Property Corner Requirements

View full size image of four-way intersection, with box showing driveways not allowed within x distance of intersection

View full size image of "T" intersection with a driveway situated at the top of the "T" and not in the marked legal crosswalk

2. Location of driveway access control mechanisms – Any driveway access control mechanisms (gates, fences, etc.) for industrial or commercial driveways must be setback a minimum of 20 feet from the street lot line.
3. Driveways per Frontage/Lot – A lot (including multiple contiguous tax lots under one ownership) with a commercial or industrial driveway or in a residential multi-dwelling zone may have more than on driveway per frontage if a minimum of 100 feet separate the centerlines of those driveways. Lots in single dwelling zones, including but limited to through-lots, lots fronting an alley, or corner lots, are only allowed one driveway per lot.
4. Alignment of driveway in relation to public right-of-way – Driveway entrances must be perpendicular to the public right-of-way. 
5. Forward Motion Requirement – In addition to forward motion requirements stipulated in PCC Chapter 33.266, a driveway accessing a roadway classified as a Neighborhood Collector or higher traffic classification must be designed to allow forward motion ingress and egress.  The City Traffic Engineer will require forward-motion on-site be demonstrated via turning movements and prepared by an Engineer with an appropriate design vehicle with a minimum of an 18-foot centerline turning radius.
6. Location on Lowest Classified Street – For any site with more than one frontage, driveway access is allowed only from the street with the lowest traffic classification per the adopted Transportation System Plan. For sites with frontages of equivalent traffic classifications, driveways should be located on the frontage with a lower bicycle classification. For houses, duplexes, triplexes, fourplexes, or sites in single dwelling zones or multi-dwelling zones and are 10,000 square feet or less in total site area with frontage on an alley, driveway access is only allowed via the alley.
7. Clear Sight Triangle

   1. At all driveways along Local Service Traffic Streets, Traffic Access Streets, Neighborhood Collectors and all residential driveways, a 15-foot by 15-foot clear sight triangle must be maintained on each side of the driveway surface, measured along the near edge of the pavement of the travel surfaces. Exemptions include driveways in alleys and buildings built at the property line. See Figure 3a.

       

      View full size image of Clear sight 15 foot sight triangle for car exiting driveway

   2. At all other driveways, clear sight triangles must be provided at the intersection of any driveway and public roadway (excluding alleys) for vehicle maneuvering from subject driveway. A clear sight triangle is formed between the decision point within the driveway (measured 10 feet from the edge of the nearest conflicting approach lane) and the point of adequate stopping sight distance (where an object height is measured vertically at typically 3.5 feet from the street grade). See Figure 3b. See Table 2 for required stopping sight distances. 

       

      View full size image of diagram showing clear sight triangle for car exiting driveway

      Table 2: Stopping Sight Distance

      Design Speed (mph	Stopping Sight Distance (feet)
      15	80
      20	115
      25	155
      30	200
      35	250
      40	305
      45	360

   3. Within the clear sight triangle, vegetation and structures must provide unobstructed visibility between 36 inches above the ground to 8 feet above the ground.
      1. References: Vegetation and structure dimensions must comply with vision clearance standards of PCC Title 16, Vehicles and Traffic; PCC Section 33.248, Landscaping and Screening, including maintenance activities per PCC Chapter 29.20, Property Nuisances; and PCC Title 32, Signs and Related Regulations.
      2. Exemptions: Certain objects within the sight triangle are exempt including: 
         1. Parked vehicles; 
         2. Street infrastructure (i.e. traffic signal equipment, streetlight equipment, street furniture, garbage receptacles, transit stops) although that infrastructure should be designed to comply with this policy or minimize impacts within the sight triangle;
         3. Trees with a trunk diameter of less than three (3) feet measured 4.5 feet off the ground (per PCC Section 11.80.020 (C) Trees with trunk diameters three (3) feet or larger will be analyzed on a case-by-case basis. Consistent with PRK-2.04, decisions about tree removal will be made by the City Traffic Engineer following consultation with the City Forester, or designee, on alternatives to tree removal.  Regardless of diameter, tree branches should be limbed/pruned in the sight triangle to improve visibility;
         4. Bushes and other plantings less than two (2) feet in width in any direction; 
         5. Poles and posts with a diameter of less than two (2) feet; 
         6. Legally established structures; and 
         7. Other objects exempted by the City Engineer or City Traffic Engineer. 
8. Narrow Corner Lots in Residential Zoning - A driveway serving a corner lot that does not meet the minimum driveway separation requirement from a corner per Paragraph D.1., above will be allowed, provided the site meets all of the following criteria. See Figure 4. 
   1. Driveway is not within the legal crosswalk (both marked and unmarked); 
   2. The lot width is less than 39 feet; 
   3. The driveway is located as far from the property corner where two streets intersect as possible while meeting applicable setbacks as required by PCC Title 33; 
   4. The driveway is a maximum of 9 feet wide; 
   5. The driveway cannot be located on another adjacent right-of-way in a manner that would meet Paragraph D.1., above. This will not apply if the other adjacent right-of-way is classified higher than a Local Service Traffic Street; and 

   6. The driveway meets all other requirements of Title 17.

       

      View full size image of House on narrow corner lot with measurements for driveway

9. Shared Driveways for Attached Housing (including duplexes, triplexes, and fourplexes) - Shared driveways are required with attached housing spanning one or more lots of two or more dwellings, regardless of ownership. The driveway design will be as identified in Figures 4 through 6. The following exceptions apply:
   1. For attached housing on existing lots with a depth of 60 feet or less, driveways are required to be shared, however, a taper will not be required. The maximum driveway width will be 20 feet without a taper (see Figure 5).
   2. For all other attached housing, driveways are required to be shared using a taper as identified in Figure 6, with a maximum driveway width of 14 feet.
   3. For residential driveway permits on corner lots, shared driveways are not required provided each driveway is located on a separate frontage, both streets are classified as Local Service Traffic streets, and the driveways meet all other dimension and locational requirements contained herein.
   4. For residential driveways on alleys, a taper is not required. 

View full size image of Attached housing with shallow lots driveway requirements

View full size image of driveway requirements for attached housing

E. Driveway Dimensions

1. Driveway width is measured lengthwise along the property line side and such measurement does not include the width of wings connecting the top of curb to the lowered curb or apron. A permit to construct a driveway in the public right-of-way is subject to the width provisions as specified below. In addition to the dimensions specified in this section, the driveway approach in the public right-of-way may not be wider than the driveway width on private property. Parking pads located on alleys are not subject to these width requirements. 
   1. Driveway Types:
      1. Residential:
         1. For single structures that include up to four units with a single-width vehicle parking area, a driveway width must be no less than 9 feet and no more than 12 feet.
         2. For single structures that include up to four units with a double-width vehicle parking area, a driveway width up to 20 feet is allowed. 
         3. For shared driveways for attached housing (includes duplexes, triplexes, and fourplexes), a driveway width from 9 feet to 14 feet maximum or 20 feet maximum, per Paragraph D9 is allowed. See Figures 5 and 6.
         4. For Middle Housing Land Divisions (MHLDs): A single-width vehicle parking area and driveway measuring between 9 feet and 12 feet is allowed for each individual unit within the MHLD.
         5. For all other residential development (excludes mixed-use), width between 20 feet and 24 feet is allowed. Exemptions:
            1. The required driveway width may be reduced to as narrow as 10 feet if:
               1. The driveway provides access to 10 or fewer parking spaces; 
               2. The driveway is located on a Local Service Traffic Street; and
               3. The site is designed to allow vehicles to exit in a forward motion.
      2. Commercial: Includes mixed-use properties. Width 20 feet minimum to 24 feet maximum. Exemptions:
         1. The required driveway width may be reduced to 10 feet if:
            1. The driveway only supports one-way vehicle movement; or
            2. The driveway only provides access to a required on-site loading space; or
            3. All of the following are true:
               1. The driveway provides access to 10 or fewer parking spaces; and
               2. The driveway is located on a Local Service Traffic Street; and 
               3. The site is designed to allow vehicles to exit in a forward motion.
      3. Industrial. Width 20 feet minimum to 40 feet maximum. Exemption:
         1. The required driveway width may be reduced to 12 feet for a driveway that only supports one-way vehicle movement.
2. A minimum of 5 feet of straight curb must separate approaches regardless of the type of driveway proposed or property ownership. 
3. Maximum Driveway Grade: The maximum grade break (algebraic difference in running grade) within a driveway or driveway approach without requiring a vertical curve must comply with Portland Bureau of Transportation driveway Standard Drawings.

F. Access Requirements for Parking Structures 

Parking structures that have no setback from the property line, and that access a Central City street or any arterial street, must provide the following at exits serving more than twenty parking spaces, unless otherwise approved by the City Traffic Engineer:

1. The building must be designed to allow exiting drivers to see pedestrians on the sidewalks approaching the vehicle exits.
2. An audio/visual warning system must be installed to warn pedestrians of exiting vehicles.