Exploring the Impacts of Street Illuminance on Nighttime Crash Severity in Roadway Segments Using a Random Parameter Ordered Probit Model

Nighttime crashes are over-represented on the US highway system. Roadway lighting, providing additional visibility by supplementing vehicle headlights, has been identified as an effective countermeasure to improve nighttime safety. However, the effect of street lighting illuminance in reducing the injury severity of nighttime crashes on roadway segments is not well-documented. This study aimed to investigate the effect of street lighting illuminance, rather than the presence of street lighting, on nighttime crash severity on roadway segments. Illuminance data were collected in the Tampa Bay area in Florida from 2012–2014 using the Advanced Lighting Measurement System and four years of crash data (2011–2014). A random parameter ordered probit model was developed based on the collected data for addressing the unobserved heterogeneity issue in the sample. The major conclusions include the following: (1) a medium illuminance level (0.4–0.8 fc) compared to a low illuminance level (< 0.4 fc) can significantly reduce the injury severity of nighttime crashes; (2) a high illuminance level (> 0.8 fc) has no significant influence on the injury severity of nighttime crashes compared to a medium illuminance level, but its effect is random (63.7% increase in injury severity and 23.7% decrease); (3) the involvement of vulnerable road users (pedestrians, bicyclists, motorcyclists) and aggressive driving are the first and second most significant factors contributing to severe injury (fatal or incapacitating) in nighttime crashes; and (4) other significant factors include injured party gender, driver age (at fault), crash type, roadway speed limit, lane configuration, pavement friction, etc.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AND40 Standing Committee on Visibility.
• Authors:
  • Xin, Chunfu
  • Wang, Zhenyu
  • Lin, Pei-Sung
  • Koh, Bomin
  • Hsu, Ping P
  • Wong, Edith
  • Chen, Tao
• Conference:
  • Transportation Research Board 97th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2018-1-7 to 2018-1-11
• Date: 2018

Language

• English

Media Info

• Media Type: Digital/other
• Features: Photos; References; Tables;
• Pagination: 13p

Subject/Index Terms

• TRT Terms: Crash causes; Highway safety; Injury severity; Luminance; Night visibility; Nighttime crashes; Street lighting; Vulnerable road users
• Geographic Terms: Tampa Bay
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01664137
• Record Type: Publication
• Report/Paper Numbers: 18-05178
• Files: TRIS, TRB, ATRI
• Created Date: Mar 23 2018 5:14PM