New nighttime roadway lighting documentation applied to public safety at night: A case study in San Antonio, Texas

Built environment and public safety professionals view street lighting as an important factor in improving the well-being of the community at night. Extant research that has examined the relationship between street lighting and public safety has found inconclusive or mixed results and has called for more extensive lighting metrics. Using new lighting measurement technologies and geographic information science, this study builds on previous work to demonstrate new metrics to consider when evaluating public safety, specifically crime and traffic accidents. Downtown San Antonio, Texas is used as a case study to explore illuminance levels on roadways and the driver's eye, and how these metrics can be used to understand the lighting characteristics of where crime and traffic accidents occur. The findings indicate that the central downtown district in San Antonio has higher illuminance levels than the existing roadway lighting guidelines while the residential downtown neighborhoods have insufficient light levels. Statistical analysis reveals that roadway illuminance levels are higher in areas where no crime occurred and driver's eye illuminance levels are lower in areas with no traffic accidents. The findings prove the usefulness of new lighting documentation techniques and support the importance of considering illuminance metrics when assessing crime and traffic accidents at night.