Evaluating Effects of Highway Median Barriers on Wildlife Movement and Mortality

Focus Area

Wildlife & Ecosystems


Natural Resources






Over 3 years

Research Idea Scope

TERI Database Administrator Notes.  Not recommended at present time by 2009 Natural Systems Subcommittee.  Subcommitee sees this topic as consistent with ID#86.

A state of the practice survey and gap analysis was published by Caltrans in 2006.  The report produced a solid foundation from which to develop and initiate field studies to investigate the effects and performance of a variety of median barrier designs on the movement and mortality of wildlife.  Hypothesis testing would be used to determine whether median barrier designs (e.g., continuous concrete barriers with scuppers) enhance or diminish the ability of a variety of species to safely make at-grade crossings and whether this affects population viability and motorist safety.Field monitoring schemes would evaluate the conservation value and efficacy of median barrier designs in reducing wildlife mortality, restoring animal movement and maintaining their populations over the long term.  Research would need to address different sized taxa (small, medium and large) and different median barrier designs (mitigated and traditional) in a variety of landscapes to ascertain performance and cost-benefits.  Comparisons would be made between sections with (mitigated) median barriers and without, in either before-after comparisons or with/without study designs. Results would be used to develop guidelines and decision support for transportation practitioners considering the installation of, or retrofitting of, highway median barriers.

Urgency and Payoff

There is an unambiguous information gap with regard to median barriers on our roadways and how they impact wildlife populations. A long-term project which replicates studies in multiple sites with a variety of median barrier designs and diverse taxa in differing landscapes would provide the opportunity for rigorous research.  This project offers the distinct advantage of widespread collaboration among transportation agencies across North America. Results would ultimately be used to provide sound decision-making guidelines and support regarding the selection, configuration, location, monitoring, evaluation, and maintenance of median barriers on highways with respect to wildlife.

Suggested By

Tony Clevenger and Angela Kociolek, Western Transportation Institute