Skip to main content
ICTD 2024 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Abstract for presentation (Poster or Podium)

Transportation Safety

Enhancing Safety in Short Tunnels: Daytime Lighting Analysis

Sunday, June 16, 2024
1:15 PM - 2:30 PM ET
Room: Galleria
Abstract: Daytime lighting is warranted when natural sunlight fails to provide sufficient visibility for tunnel users. According to the AASHTO Roadway Lighting Design Guide, no supplemental lighting is required if the tunnel is less than 80 ft in length, while supplemental lighting is needed if the tunnel length exceeds 410 ft. However, no guidance is provided for tunnel length in between.  As such, for the short tunnels in this particular range, specific guidelines are necessary for daytime lighting warrant analysis and determination of the low-visibility area for lighting installation. Besides the tunnel length, light penetration in short tunnels is dependent on a variety of factors, including tunnel type, median type, orientation, whether the tunnel is straight or curved, reflectivity of pavement and interior surfaces, traffic volume, presence of pedestrians or cyclists, etc. Short tunnels, particularly on clear and sunny days, may experience visibility challenges due to the significant contrast in luminance between the tunnel interior and the exterior environment. This stark difference can create a “black hole” or "black frame" effect, temporarily blinding drivers and impeding their ability to detect potential hazards or small objects within the tunnel.  To fill this practice gap and address the associated safety concerns, field measurements of luminance and illuminance have been conducted for a number of short tunnels in Georgia. This research study leveraged this invaluable dataset to develop an analytical process consisting of decision trees and regression models, aimed at achieving two primary objectives: (1) evaluating the necessity of daytime lighting in short tunnels by considering influential variables, and (2) delineating the specific areas within a tunnel that necessitate artificial illumination. The findings and recommendations derived from this study are poised to enhance the safety of short tunnels during daytime.

Learning Objectives:

Attendees can expect to learn the following from this session:
  • Learn tunnel safety regarding daytime lighting conditions.
  • Understand the complexity of situations associated with driver adaptation to different lighting conditions within and outside of short tunnels.
  • Learn how machine learning techniques, especially joint embedding, clustering, and decision trees, can be applied to field data to detect visibility conditions within short tunnels.