Research has shown a positive safety impact of lighting at isolated rural intersections. Due to factors such as the lack of risk-based warrants, lack of design guidelines relevant to isolated rural or low volume areas, and concerns about the associated costs and maintenance requirements, lighting practices for isolated rural intersections vary significantly among different states. A number of roadway lighting guides are available nationwide, among which are the American Association of State Highway and Transportation Officials (AASHTO) Roadway Lighting Design Guide, the Illuminating Engineering Society of North America (IES) Recommended Practice for Lighting Roadway and Parking Facilities RP-8-18., and the FHWA Lighting Handbook. However, these guides contain limited information on isolated rural intersection lighting.
The objective of this synthesis is to document current intersection selection criteria, design, maintenance, and operation practices for isolated rural intersection lighting.
Information to be gathered includes, but is not limited to:
· Intersection selection criteria used for lighting in isolated rural intersections.
· Design criteria used for lighting in isolated rural intersections, and how they are effected by other roadway safety elements. (e.g. geometry, traffic control, incidental lighting)
· DOT’s current practice and written policy on isolated rural intersection lighting design and application.
· Low-cost technological and design solutions in use for isolated rural intersection lighting.
· DOT experience with solar-powered or other alternative power systems, under what circumstances are they used, what types of installations are used, their effectiveness, and additional considerations like adaptive lighting.
· Maintenance considerations, including lifecycle cost and LOS requirements.
· Lighting metrics used and evaluated by DOT’s. (e.g., illuminance levels, correlated color temperature, luminaire type and distribution, uniformity ratios)
· Effect of intersection type on lighting considerations (e.g. at grade crossing, stop controlled, roundabout, restricted crossing u-turns)
· Cost-sharing and cost-reimbursement policies influence on the decision to add or exclude lighting.
· Existence of lighting guidance on other intersection types like isolated access points or isolated at grade rail crossings.
Information will be collected through literature review, survey of DOTs, and follow-up interviews with selected agencies for the development of case examples. Other sources such as the National Association of County Engineers, and the Local Technical Assistance Programs may be contacted. Information gaps and suggestions for research to address those gaps will be identified
Richard M. Dearstyne, New York State DOT
Robert L. Graham, Jr., Georgia DOT
Robert G. Hall, North Carolina DOT
Mylinh Lidder, Nevada DOT
Eugene R. Russell, Sr., Kansas State University
Robert Small, Moldonando-Burkett
Sue Zarling, Minnesota DOT
Hillary Isebrands, Federal Highway Administration
Bernardo Kleiner, Transportation Research Board
M. Andre Primus
First meeting: September 19, 2019, Washington, DC
Teleconference: October 29, 2019
Second meeting: June 18, 2020