Roadway Standards Section 260 - Traffic Signals, Flashers & Communication

260.1 Traffic Signal Approval

A traffic signal may be approved if the criteria of this section are met. 

260.1.1 Traffic Analysis

A traffic analysis is required prior to the approval of a traffic signal.  Analysis requirements shall be based upon Section 295 and should include the following:

1. An analysis of other alternatives is required prior to the approval of a traffic signal.  Possible alternatives to traffic signal installation include right and left turn lane additions, other lane additions, alternative routes via planned or existing roadways, roundabout installation as well as modifications to traffic control. 
2. An analysis of capacity, queuing and safety both with and without the proposed traffic signal.  Additional roadway improvements may be required based upon this analysis to ensure safety is maintained with the installation of a traffic signal, notably left turn lanes. 
3. Unless the Comprehensive Plan specifically calls for a traffic signal, an analysis of alternatives shall establish that a roundabout is impractical or unreasonable before a traffic signal will be approved.  The analysis shall include preliminary geometry, a comparative estimate of right-of-way impacts of a traffic signal versus a roundabout, benefit/cost ratio, and a capacity analysis. 
4. Evidence that the criteria of Section 260.1.2 can be met. 
5. In locations with other traffic signals nearby, the proposed traffic signal shall not unacceptably decrease the corridor bandwidth.
6. A consideration of bicycle and pedestrian safety and mobility. 
7. An analysis of traffic signal phasing including:
8. Phasing analysis for different peak periods.
9. Evaluation of warrants for left turn protected, protected/permissive, and permissive/protected signal phasing, and protected right turn signal phasing based upon ODOT's Traffic Signal Policy and Guidelines.

260.1.2 Traffic Signal Warrants

1. New traffic signals at intersections on County roadways shall meet at least one, preferably several, of the traffic signal warrants of the current version of the MUTCD prior to the approval of a traffic signal.
2. Traffic signals meeting only peak hour volume warrants should only be approved if the intersection serves a special trip generator with unique peak traffic characteristics and evidence is provided that the traffic signal is a benefit to the public.

260.1.3 Traffic Signal Spacing

Traffic signals should be separated from existing or planned traffic signals a minimum of ¼ mile apart unless evidence supports adequate long term operations at a lesser spacing.  If an existing comprehensive plan illustrates spacing closer than this spacing, additional long term analysis is not required.   

260.2 Traffic Signal Design

1. Traffic signal design should be based upon the ODOT Traffic Signal Design Manual, Oregon Standard Drawings TM 400 and TM 600 Series, Clackamas County traffic signal drawings and details and the MUTCD.
2. Plans shall be consistent with the results of the traffic analysis performed under Section 260.1.1. 
3. Signalized intersections should be accompanied by channelized left turn lanes on the major street, on minor street arterials and collectors, and designed per Section 250.8.8.
4. Signalized intersections may be accompanied by channelized right turn lanes on the major street and minor street arterials and collectors as warranted by Section 295.19.1 and designed per Section 250.8.8.
5. Signalized intersections with pedestrian access routes shall comply with ADA requirements as described in the most recent version of ODOT's Traffic Signal Policy and Guidelines including accessible pedestrian signals and push buttons complying with the MUTCD, and meeting the provisions of PROWAG.
6. All plans shall be prepared under the direction of and stamped by an Engineer with expertise in traffic engineering.

260.3 Traffic Signal Materials

Materials used in the construction of traffic signals shall be approved by Engineering and comply with the Oregon Standard Specifications for Construction and the Clackamas County traffic signal drawings and details.

260.4 Material Submittals

Prior to signal construction, the materials to be used on the project shall be submitted to Engineering for review and approval in the form of standard Oregon traffic signal blue sheets, green sheets, red sheets and applicable cut sheets.

260.5 Traffic Signal Funding and Agreements

If approved in conjunction with a development, the following shall apply:

1. The applicant shall be required to enter into necessary agreements to fulfill the obligations of this section.
2. The applicant shall provide funds for necessary signal timing synchronization with existing traffic signals systems.
3. If approved at the intersection of a private driveway with a public roadway, the applicant shall be required to provide funds equal to 20 years of the maintenance and power of the traffic signal.
4. The applicant shall provide the necessary right-of-way and/or easements for County maintenance of the traffic signal appurtenances constructed at a development's private driveway or along a development's frontage.
5. The applicant shall maintain on-site pavement markings and signage in such a way that is consistent with the approved design.  Markings and signage shall be maintained in a way that is compliant with the MUTCD. 

260.6 Underground Communication Conduit

As required by Engineering, developments within the UGB shall be required to install fiber optic ready conduit under any of the following conditions:

1. When the development is required to install landscape strip and/or sidewalk along a collector or arterial roadway, the length of the work exceeds 200 feet, and is along a planned fiber optic network.
2. When the development abuts existing fiber optic conduit and extending the fiber optic conduit would extend a planned fiber optic network.
3. When the conditions of Section 260.7 apply.

260.7 Fiber Optic Communication

As required by Engineering, the installation of new traffic signals shall be accompanied by the installation of fiber optic conduit and fiber optic cable, unless existing, between the proposed traffic signal and adjacent traffic signals.

260.8 Flashers in School Zones

New schools or existing schools with an expansion of 20% floor area or greater shall be required to install school zone flashers on roadways that are classified as arterial or collector roadways if the proposed or existing school speed zone signing supports a school speed 20 MPH zone and the County supports a school speed zone installation.  In addition to school zone flashers, radar speed signs may be required along arterial roadways.

The applicant shall be required to provide funds equal to 20 years of the maintenance and power of the school zone flasher and/or radar speed sign.