After four years of debate, Costa Rica’s Legislative Assembly approved Law 23.176, which mandates the incorporation of wildlife crossings into the country’s public infrastructure to ensure the safe movement of wildlife amid habitat fragmentation.
This has long been a problem for Guanacaste, not only because of the lack of infrastructure but also because much of what exists is not functional. A team of specialists from the organization Panthera warns that urgent action is needed from authorities and the construction companies in charge of road projects.
The “Stretch of Death”
The Cañas-Limonal stretch, which connects the Central Valley with the province of Guanacaste, is one of the most critical areas in the entire country for wildlife.
Along the slightly more than 20-kilometer Cañas-Limonal stretch, Panthera estimates that more than 16,000 animals are killed by vehicles each year. Of these, around 6,000 are amphibians, such as toads and frogs.
Panthera, in collaboration with the Inter-American Development Bank (IDB), monitored this section between 2024 and 2025, conducting field surveys and using camera traps.
The study recorded the presence of 88 vertebrate species, including pumas, ocelots, congo monkeys, white-faced monkeys, red howler monkeys, otters, deer, and peccaries. Of that total, at least 14 species are highly vulnerable, as their populations are considered threatened on national or international lists.
Of the species most at risk when attempting to cross the highway, these 14 species are the most vulnerable because their populations are endangered or threatened.
The well-known Route 1 is not a highway without environmental measures. It already features overpasses for arboreal species—which spend most of their time in trees—underpasses, and signage warning of animal crossings.
Types of wildlife crossings and ecological connectivity infrastructure.
Daniela Araya Gamboa, a scientist at Panthera, explained to La Voz that several of these structures remain incomplete and unusable by animals.
For example, the underpasses still lack dry walkways in the adapted drainage systems and the mesh that should guide wildlife to a safe place to cross, while other crossings also lack fences to prevent animals from directly accessing the road surface.
Although wildlife crossings are indeed used by different species, mortality remains high in some segments where these structures already exist.
Based on the studies conducted, the group of experts concludes that the crossings, on their own, do not reduce roadkill. To be functional, they must operate as a “complete system,” including exclusion fences, culvert modifications, constant maintenance, and designs adapted to the species that use each site.
According to Araya Gamboa, following the assessment, the Ministry of Public Works and Transportation has already implemented some solutions.
According to the specialist, many animals do not even attempt to cross. Noise, vehicle speed, nighttime lights, and exposed pavement cause them to perceive the road as a hostile environment.
What’s next with the new law?
Daniela Araya Gamboa told La Voz that this law—which organizations have been advocating for over five years—is the “icing on the cake” for the work being done by civil society and for efforts made “in good faith” when building roads and highways, since no regulatory framework previously existed in this area.
The new law, approved by a unanimous vote, applies not only to future projects but also to existing and operational infrastructure when replacement, rehabilitation, improvement, expansion, or maintenance work is carried out.
As a result, infrastructure designed for wildlife must be included in project budgets, starting from the planning and pre-investment stages.
Now, both the Ministry of Public Works and Transportation (MOPT) and municipalities and other public entities wishing to build public infrastructure must coordinate and reach an agreement with the National System of Conservation Areas (Sinac) regarding the inclusion or exclusion of wildlife crossings based on technical and scientific criteria, taking into account mortality records and complaints filed through the Environmental Complaint Processing System (Sitada).
Once the law’s implementing regulations are finalized and approved, Sinac will have a maximum of 24 months to begin identifying “vulnerable points” on highways in order to implement the necessary improvements.
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