Details:

Creators:
Edwards, Christopher J.
Corporate Creators:
University of Minnesota. Department of Mechanical Engineering. HumanFIRST Program
Corporate Contributors:
Minnesota. Dept. of Transportation. Research Services & Library
Subject/TRT Terms:
[+]
Illuminance
Rural Intersections
Collisions
Intersections
Isolated Intersections
Lighting
Luminance
Rural Transit
Street Lighting

Publication/ Report Number:
MN/RC 2015-05
Resource Type:
Tech Report
Geographical Coverage:
United States ; Minnesota
United States ; Minnesota Less -
Edition:
Final report
Corporate Publisher:
Minnesota. Dept. of Transportation. Research Services & Library
Abstract:
A number of studies have linked the benefits of roadway lighting to a reduction in crash rates at night for a variety

of roadway types including rural intersections. Assessing the effectiveness of intersection lighting has primarily

relied upon crash database modeling comparing lighted intersections to unlighted intersections. The current

research effort gathered similar metrics for comparison but also measured the amount of lighting within isolated

rural intersections. Sixty-three intersection locations were chosen for lighting measurement from six different

counties within Minnesota. A vehicle mounted illuminance meter data collection system was used to collect data at

each intersection. The data collection system utilized five separate illuminance meters and captured horizontal

illuminance while driving through all 63 intersection locations. Following data collection, a series of negative

binomial regression models were used to assess the horizontal lighting level in conjunction with the nighttime crash

ratio, intersection configuration type, and proximity of an intersection to a curve in the roadway. The first model

used data from the lighted an unlighted intersections. The results showed that across all intersections, an increase in

the average horizontal illuminance (3.91 lux) by 1-lux (~0.09 fc) reduced nighttime crash rates by 9%. A second

model used only lighted intersection data and showed an increase in 1-lux from average (6.41 lux) reduced crashes

by 20%. A third and final model used unlighted intersections only. A 1-lux increase from average (0.20 lux) or

increasing illuminance to lighted levels (as defined by the modeling), reduced nighttime crash ratios by 94%.

Intersection configuration and proximity to curves also affected the nighttime crash ratios. The results of this effort

are discussed in terms the impact of horizontal illuminance on crash rates. Additional items discussed include

thresholds for minimum and maximum lighting levels and future research investigating and validating these efforts.


Format:
PDF
Funding:
2013012 ; (c) 99008 (wo) 39
2013012 ; (c) 99008 (wo) 39 Less -
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:1bce6d5cca68a7b8268f0d83dc5e366e97c32c1f5a921af92a1890ea1091b327
File Type:

Supporting Files

• No Additional Files

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