Why lighting is important
Studies show strong links between street safety and lighting. The presence of lighting reduces crash rates compared to unlighted streets by increasing street users’ visibility. The Illuminating Engineering Society describes how “for a pedestrian, this can mean better visibility of the surrounds and the sidewalk, while for the driver of a motor vehicle [or someone bicycling], it will mean time to stop or maneuver around an obstacle.”
Studies also show strong associations between street lighting and neighborhoods’ sense of community, physical activity and public safety. For example, street lighting can lead to reductions in crime and fear of crime and increase pedestrian street use after dark.
The City of Portland owns more than 50,000 streetlights that were recently converted to LED lights (see Figures 1 and 2), which use 50% less energy than previous lights and provide better illumination. Portland has many types of street users and street characteristics that support different lighting levels. The Portland Bureau of Transportation (PBOT’s) Signals, Streetlighting, & ITS Division maintains and reviews lighting modifications in the City’s streets.
|Figure 1. Older High Pressure Sodium lights compared to modern LED lights|
Aerial view of NE Cully Blvd. with older High Pressure Sodium lights.
The same location following LED lighting installation.
Defining an adequate/safe amount of lighting
PBOT’s street lighting standards provide lighting values for different street classifications (view map of street classifications).
In 1990, PBOT implemented an infill policy for residential streets. This policy set maximum spacing standards for practical lighting infill of local streets that previous policies did not cover. As part of this policy, the City developed a standard detail identifying the different light pole layout configurations.
The street lighting guidelines provide illuminance lighting values for different street classifications. Minimum lighting levels rise with street functional classification. The guidelines suggest the brightest lighting for Major Traffic/Major Transit/Traffic Access streets, and lower lighting levels for District Collector and Neighborhood Collector roadways. Local Service roadways have the lowest lighting levels. Wider arterial streets are more likely to require two-sided lighting or other lighting solutions to meet uniformity guidelines.
|Figure 2. Overhead two-sided LED lighting at street level|
Street-level view of two-sided lighting at NE Cully Blvd. & Sumner St. (Photo: S. Bussey)
Higher lighting levels are recommended at intersections and mid-block pedestrian crossings, and sometimes supplemental pedestrian scale lighting is used if it is determined that overhead lighting is inadequate (see Figure 3). PBOT typically mounts pedestrian scale lighting at 14 ft compared to overhead “cobra-head” lighting that is mounted at 30-40ft.
|Figure 3. Pedestrian scale and overhead lighting|
Pedestrian-scale lighting (left) and overhead lighting (right) at SE Division & 142nd Ave. (Photo: S. Bussey)
Portland has some special lighting districts. City code notes that “all street lights shall be a standard overhead fixture except in areas where it is determined by the Commissioner In Charge of the Bureau of Transportation that specialty lighting would substantially enhance a unique characteristic of the district.”
How we prioritize investments in updated lighting
PBOT recently finished a three-year city-wide LED conversion of more than 50,000 cobrahead and ornamental lights. This investment was primarily funded through future savings on energy consumption and maintenance/repair.
As part of the Safety Action Plan for Outer SE Division Street, the City is planning to supplement existing lighting on outer SE Division (82nd to 174th) that will improve the uniformity of lighting in this corridor.
PBOT performs an equity analysis using its Equity Matrix to inform lighting improvements. The matrix considers the demographic variables of race, income and Limited English Proficiency within Census Block groups in Portland.
The City’s development code requires privately or publicly funded projects with streetlights corresponding to City lighting standards. Design, plans and specifications for streetlights to be installed or altered shall be first approved by PBOT. The full cost of providing the street lighting improvements shall be paid by the permittee or funding source used for the street construction costs.
Engineering staff in PBOT’s Signals, Street Lighting and ITS division conduct monthly “night drives” to evaluate lighting needs and identify street light outages. PBOT also coordinates with City partners to prune overhanging foliage when it seriously obstructs the light intended for the pavement and sidewalk.
Please contact PBOT’s Signals, Street lighting & ITS Division at 503-823-5185.
Report a street light outage at 503-865-LAMP (5267) or online.
*Illuminating Engineering Society, 2014. Roadway Lighting. ANSI/IES RP-8-14, p.1.