Walking After Dark: A Sidewalk Illumination Case Study in Cedar City, UT

Sidewalks are an important part of public space, but they are becoming increasingly dangerous, especially at night. Therefore, it is important that sidewalks are adequately illuminated to meet the safety, comfort, and accessibility needs (i.e., provide high levels of pedestrian reassurance) to sidewalk users. The objective of this case study was to quantitatively measure and subsequently explore the spatial and statistical distributions of light intensities along the sidewalks that surround Southern Utah University in Cedar City, Utah. A secondary objective was to develop a set of “adequate lighting” guidelines (i.e., 5 to 10 lux) to help identify areas that could benefit from sidewalks lighting enhancements. A digital light meter was used to measure horizontal light intensity, in lux, at a systematic sample of 208 points along the sidewalks within the study area. Geographic coordinates were also collected for each sample observation to enable mapping and spatial analysis of the light intensity data. Results indicate 61% of the observations have lux values equal to zero (complete darkness), 13.4% met or exceeded the minimum guidelines, while 4.3% fell within the “adequate lighting” guidelines adopted by this case study. These results suggest that sidewalks are too dark in too many places to provide reassurance to sidewalk users in the study area. The mapping and spatial analysis results from this case study also provide information to support targeted visibility enhancements of sidewalks within the study area. KEY WORDS: Lighting; Optimum Illuminance; Luminometer; Sidewalks; Pedestrians; Safety; Security; Reassurance