Research Roadmap for Environmental Effects of Roadway Lighting on Fauna and Flora

Focus Area

Wildlife & Ecosystems


Natural Resources






2-3 years

Research Idea Scope

BACKGROUND There is a need to investigate the effects of artificial light on a growing list of bats, birds, insects, fish, and other members of the environmental community which may derive adverse consequences from poorly or even well-designed roadway lighting. Transportation agencies are facing growing opposition to the use of nighttime lighting as a countermeasure to improve roadway safety from environmentalist concerned with potential consequences to the environment. Roadway lighting has been shown to measurably reduce nighttime fatal crashes in areas where it has been implemented. However, roadway lighting can have a negative effect on certain species of insects and animals through attraction and disorientation or by disrupting their natural habitats. Sea turtle hatchlings are an example of being drawn to peril by the presence of artificial light at night. They can be confused by outdoor lighting instead of instinctively navigating by moonlight safely to the ocean from their nests. The scope is not entirely defined in terms of the number of individual species of fauna and flora which may be adversely impacted. Also unclear is the means by which any adverse effects can be resolved. Some have proposed that outdoor lighting should be completely banned from sensitive areas where species could be potentially harmed. Some evidence would suggest that light sources are acceptable in areas of concern (i.e., road through nature preserves) as long as the blue content of the light spectra is minimized or eliminated. This however may not be true in all cases and is not sufficiently quantified for practitioners engaged in lighting design. Before millions of roadway luminaires are converted to the new technology of LED there needs to be a better understanding of what light level and spectrum can be installed in potentially sensitive locations which will do no harm. This effort is fundamental in safeguarding natural ecosystems and being responsible citizens of the environment. A research roadmap is intended to establish the basis for informed decisions by lighting designers with the support of biologists and environmental researchers. RESEARCH OBJECTIVE The objective of this research is to develop a Research Roadmap addressing the policy, planning, and implementation issues facing federal, state, and local transportation agencies currently engaged in the conflict between nighttime lighting’s positive effect on roadway safety and negative effect on the environment. The roadmap should consider the scope and magnitude by which outdoor lighting in general and roadway lighting more specifically influences species of plants and animals in an adverse manner (i.e., sea turtles) and propose solutions to mitigate these impacts. This roadmap will also serve to inform the work of researchers currently working independently by bringing together both biologists and lighting specialists to pioneer solutions. IMPLEMENTATION CONSIDERATIONS AND SUPPORTERS Luszcz, Mark, Delaware DOT, AASHTO Tech Committee on Roadway Lighting, Chairman PROBLEM STATEMENT AUTHOR(S) Seppelt, Mark, Illinois DOT, AASHTO Tech Committee on Roadway Lighting, Panel Member OTHERS SUPPORTING THE PROBLEM STATEMENT AASHTO Technical Committee on Roadway Lighting, Luszcz, Mark, Delaware DOT 302-659-4062 [email protected] POTENTIAL PANEL MEMBERS Zarling, Susan, Minnesota DOT, AASHTO Tech Committee on Roadway Lighting, Panel Member St. Clair, Daryl, Pennsylvania DOT, AASHTO Tech Committee on Roadway Lighting, Panel Member Bosin, Anna, Alaska DOT, AASHTO Research Advisory Committee

Urgency and Payoff

URGENCY AND POTENTIAL BENEFITS The magnitude of potential impact must be determined before incorrect lighting designs are deployed in a nonrecoverable fashion. Currently DOTs around the country are converting high pressure sodium (HPS) luminaires to light emitting diode (LED) roadway fixtures as HPS is no longer supported by most fixture manufacturers. The correlated color temperature differs between these two light sources and can differ among LED luminaires depending on which LED is selected. Likewise, the spectrum can vary in blue light content depending on the specific LED fixture selected. A proper understanding of the impacts of LED roadway lighting on fauna and flora can prevent a large deployment of fixtures throughout the country that are not optimally tuned to the needs of the environment.

Suggested By

Mark Seppelt Wi-Skies LLC (former Illinois DOT)

[email protected]