Transportation Overview

North Cooper Mountain has primarily rural roads that serve urban transportation needs. The key challenge for North Cooper Mountain is how to plan for growth and ensure solutions are delivered for multiple inter-related needs: high volumes of regional through-traffic; intersections and road sections with known safety and capacity issues; almost no existing pedestrian and bicycle system; and the vision to provide transportation options. Transportation planning for the North Cooper Mountain area is folded into the broader transportation planning for the Cooper Mountain Concept Plan area.

The following objectives were established through the South Cooper Mountain Concept Plan (SCMCP) to address the identified transportation issues:

Disperse and balance regional traffic

It is well documented that north-south traffic is over-reliant on one corridor - the Roy Rogers/175th to 170th Avenue corridor. The solution is to reduce that reliance and disperse regional flows through a combination of improvements and new connections that result in a more complete network. Key projects include: 
  1. improving 175th at high priority locations such as the "kink" and the Kemmer/175th Avenue intersection;
  2. connecting 175th Avenue to 185th Avenue via Kemmer Road and a new road east of 190th;
  3. realigning the three 90-degree corners of Tile Flat and Grabhorn Roads;
  4. improving Scholls Ferry Road to 5 lanes west of 175th to Tile Flat Road; and 
  5. connecting Tile Flat Road to Roy Rogers Road (long term). These elements are illustrated within the South Cooper Mountain Transportation Framework map.

Provide a well-connected street network

The SCMCP's Transportation Framework set the stage for a connected, walkable local street system that provides transportation choices by incorporating active transportation elements. The SCMCP did not specify any new "point A to point B" collector streets and neighborhood routes in North Cooper Mountain. Local street connectivity is required with development.

Provide a functional pedestrian bicycle network

The overall strategy is to provide many types of facilities that will achieve the vision and can be feasibly implemented. The specific strategies and recommendations are to: 
  1. ensure all streets are "complete" by providing for pedestrians and bicycles as well as vehicles;
  2. plan for multi-use paths that parallel one side of perimeter arterials that frame the area; and 
  3. complete the Cooper Mountain Regional Trail that provides access to and through resource areas and to Cooper Mountain Nature Park.

Be transit-ready 

The SCMCP anticipates longer-term, limited-stop commuter-oriented transit service from Sherwood to Hillsboro along Roy Rogers Road and 175th Avenue.

Roadway Framework

Key elements of the transportation framework are summarized below.

Arterial Roads

A new connection from 175th Avenue to 185th Avenue is proposed. Between Kemmer and Gassner Roads, the alignment of the new road is proposed to curve around the west side of the stream corridor. Kemmer Road is proposed to be improved to function as an arterial from 175th to where the curve begins, around Mayberry Place. Improvements to the intersection of 175th Avenue and Kemmer Road will be needed to address safety issues and increase capacity.

Based on need identified in the SCMCP, the 2014 Washington County Transportation System Plan update redesignated Tile Flat and Grabhorn Roads adjacent to the planning area from Collectors to Arterials. The redesignations result in a consistent functional classification from Scholls Ferry Road to SW 209th Avenue. Washington County's rural Arterial standard is two travel lanes with turn pockets as needed. The SCMCP proposes realignments to smooth the three sharp 90 degree corners along Grabhorn Road in order to improve safety. 209th Avenue is planned by the City of Hillsboro as a 5-lane Arterial between Farmington Road and Tualatin-Valley Highway.

Collector Roads

Weir Road is shown extending westward to 175th Avenue and ultimately across 175th Avenue north of Winkelman Park to tie into other future streets in the Urban Reserve Area. The extension to Weir Road between SW 170th Avenue and SW 175th Avenue is consistent with the Beaverton and Washington County Transportation System Plans.

Bicycle & Pedestrian Framework

Provision of a diverse and connected bicycle and pedestrian network is one of the great opportunities for Cooper Mountain. North Cooper Mountain has one proposed Regional Multi-Use Trail: the Cooper Mountain Regional Trail. This trail will ultimately connect the regional Westside Trail to the planned Reedville Trail (formerly called the BN Powerline Trail) as well as linking to Cooper Mountain Nature Park.

While the ultimate trail widths and designs will be determined in the future, the following trail description was recommended by the SCMCP for planning purposes:

Regional trails provide connections between communities and to regionally significant features and destinations. These are assumed to be paved paths that accommodate both pedestrians (including those with disabilities) and bicyclists. They may follow roads, separated from the roadway by a landscaped area, or be located in their own separate right-of-way. Trail width may range from 10 to 14 feet, depending on context and surrounding constraints (with 2 foot gravel shoulders wherever feasible). These elements are illustrated within the South Cooper Mountain Concept and Community Plans Bicycle and Pedestrian Framework Plan map.