Lighting

The primary objective of this report is to present statistically reliable conclusions relative to the changes in crash frequencies and other crash characteristics at isolated rural intersections associated with the installation of street lighting. It was found through a comparative analysis of over 3,400 rural intersections and a Before versus After analysis of a sample of 12 intersections that the installation of street lighting reduced both nighttime crash frequencies (25% to 40%) and crash severity (8% to 26%). A Benefit – Cost analysis using statistics from the Before versus After analysis found that crash reduction benefits associated with the installation of street lighting at rural intersections outweigh the costs by a wide margin. As a result of the analysis, it was concluded that the installation of street lighting at rural intersections is a low cost and very effective strategy for mitigating nighttime crashes. This strategy should be added to the traffic engineer’s toolbox and agencies should be encouraged to increase the use of streetlights at rural intersections in order to reduce crashes and improve motorist guidance. It was also concluded based on a comparison to the results for other recent research that the use of street lighting to reduce nighttime crashes at rural intersections would likely be far more effective than either rumble strips or flashing overhead beacons.

This Technical Summary pertains to Report 2018-27, “Re-Tightening the Large Anchor Bolts of Support Structures for Signs and Luminaires,” published August 2018.

These appendices pertain to report 2016-17, Implementation of LED Roadway Lighting. Appendix A: Relume Vue V400 LED Luminaire Appendix B: Accuenergy Acuvim II Data-Logging Power Meter Appendix C: Collected Power Meter Data Appendix C-1: Initial Data Download #1, June 28, 2013 Appendix C-2: Data Download #2, November 13, 2013 Appendix C-3: Data Download #3, February 14, 2014 Appendix C-4: Data Download #4, May 17, 2014 Appendix C-5: Data Download #5, August 13, 2014 Appendix C-6: Data Download #6, December 10, 2014 Appendix C-7: Data Download #7, April 11, 2015 Appendix C-8, Final Data Download #8, August 1, 2015 Appendix D: Minolta CL200A Chroma Meter Appendix E: Quarterly Color Temperature Readings Appendix F: Relume 400 Photometry

This Implementation Summary pertains to Report 2016-17, “Implementation of LED Roadway Lighting,” published May 2016.

This Technical Summary pertains to the LRRB-produced Report 2015-05, “Lighting Levels for Isolated Intersections: Leading to Safety Improvements,” published January 2015.

This Technical Summary pertains to the LRRB-produced Report 2013-04, “46th Street Pilot Street Lighting Project,” published January 2013.

Mn/DOT maintenance and construction vehicles are required to have emergency lighting to ensure the safety of workers and motorists. The current standard for Mn/DOT snowplows is high-intensity discharge strobe lighting, or HID. In an effort to reduce maintenance costs, Mn/DOT is exploring the possibility of replacing HID on snowplows with light-emitting diodes because LED-based strobe lighting is more efficient and reliable than HID lighting. However, observation suggests that under certain conditions and from certain angles, LED lighting is less visible than standard HID lighting and so may not be as safe. Further, very little data is available about the effectiveness and safety of using LED lights on snowplows. For Mn/DOT officials to make an informed decision about whether to move to LED lighting on snowplows and other highway maintenance and construction vehicles, they needed to consider the results of comprehensive testing of this new solution.

This Technical Summary pertains to the LRRB-produced Report 2006-35, “Safety Impacts of Street Lighting at Isolated Rural Intersections—Part II,” published September 2006.

MnDOT is interested in the expected service lives of traffic signals, roadway lighting and overhead sign structures; preventive maintenance and inspection activities and schedules; cost–benefits associated with preventive maintenance and inspection strategies; and the criteria used to determine asset replacement. This Transportation Research Synthesis presents findings from a survey of select transportation agencies and a literature search of relevant national and state practices, research and guidance.

The Local Road Research Board (LRRB) was interested in more information about lighting roundabouts effectively but efficiently to improve pedestrian safety, and more generally in a synthesis of information that could serve as a starting point for review of several topics in roundabout lighting.