Applied Road and Rail Ecology

TRIEKOL – Applied Road and Rail Ecology

Vad är TRIEKOL? / What is TRIEKOL?
TRIEKOL är Trafikverkets forskningsprogram om transportinfrastrukturens inverkan på biologisk mångfald och landskapsekologi.

TRIEKOL is the research program of the Swedish Transport Administration (STA) on the impact of transport infrastructure on biodiversity and landscape ecology.

Syfte / Aim

Målet med forskningsprogrammet är att ta fram metoder och kunskap som transportsektorn behöver för att bibehålla, och om möjligt förbättra, ekologiska funktioner och kvalitéer i landskapet. Arbetet inom programmet har en direkt koppling till Trafikverkets pågående verksamhet och resultaten används för utveckling av nya riktlinjer, planering av nya investeringsprojekt och vid utveckling av drift och underhåll av befintliga vägar och järnvägar.

The aim of the research programme is to develop knowledge and methods that can help the transport sector to maintain and, where possible, improve the ecological functions and qualities of the landscape. The work within the program has a direct link with ongoing operations of STA, and the results are used to develop new guidelines, planning new investment projects and in the development of maintenance of existing roads and railways.

Programperioder / Program periods

TRIEKOL har påbörjat sin tredje programperiod (se mer om den här), vilken omfattar åren 2017-2022. Forskningsprogrammet är indelat i flera delprojekt. De två tidigare programperioderna TRIEKOL I och II omfattar åren 2009-2015 (se mer om resultaten från period I och II här).

TRIEKOL has started its third program period (see more about it here), which includes the years 2017-2022. The research program is divided into several subprojects. The two earlier program periods TRIEKOL I and II includes the years 2009-2015 (see more about the results of period I and II here).

Språk / Language

Hemsidan är tillgänglig på både svenska och engelska, du kan byta språk när du ser en flagga som denna och via huvudmenyn.

This website is available in both English and Swedish, you can switch language when you see a flag as this one and in the main menu. 

Prenumerera på nyheter

Ta del av nyheter från TRIEKOL:s forskning via e-postlistan för svenska IENE-nätverket.


Den 21 april 2021 håller SLU Centrum för biologisk mångfald (CBM), Trafikverket och svenska IENE ett webinarium om värdefulla träd vid vägar. Syftet är att sätta värdefulla träd i infrastruktur i ett sammanhang, både ur ekologisk synvinkel och i ett datahanteringsperspektiv. Mer information finns på Svenska IENEs hemsida.

Ongoing research

Wildlife adaptation of existing bridges

Conventional bridges are used by wildlife to various extent and could with relatively small efforts be adapted to further facilitate wildlife use.

In this subproject we monitor and compare wildlife’s use of existing bridges before and after wildlife adaptation. The main type of improvement that is tested is screening, but to some degree also restriction of human use will be tested.

Level crossings and wildlife warning systems

Level crossings may provide a cost-efficient alternative to under- and overpasses, even if only for larger species and under certain conditions. The idea with such passages is that the animals should be directed to certain shorter sections of a road, where the drivers are alerted for animals on or near the road.

In this subproject we monitor the performance of level crossings in terms of wildlife use and connectivity between roadsides, and the effect on wildlife accidents and driver behaviour.

Over- and underpasses for larger wildlife

Several over- and underpasses targeted particularly for larger wildlife has been built or are currently in construction in Sweden. These varies in design, vegetation and other habitat components in and around passages. Some design parameters are highly cost driving, and better knowledge of design details is needed to make future constructions more cost-efficient. 

In this subproject we monitor wildlife’s use of a number of over- and underpasses, and compare performance depending on size and design, and to a degree on siting and landscape type/geographical region.

Modeling of permeability and mortality effects on wildlife populations

A model that evaluates the effects of infrastructure permeability and traffic mortality on population viability criteria has previously been developed. So far, the model has only been applied to generalized, simplified landscapes. 

In this subproject the current model is applied to a real Swedish landscape, thereby validating the previous results by running the model in real-world landscapes. A summary functionality assessment of the model in real-world mitigation planning will be conducted.

Effect of noise measures for birds

While a number of measures to reduce noise for humans are used, their performance for birds have not yet been tested. To enable cost-effectiveness analyses of noise reduction in important bird areas, the reduction effect of different measures need to be better known.

In this subproject we study the effects of noise mitigation along existing infrastructure near important bird habitats. 

Amphibian passages

Tunnels in combination with guiding fences are standard mitigation measures for roads near amphibian habitats. However, the monitoring of such measures often fails to answer whether the two goals (lowered roadkill and barrier effect) are reached, and accordingly available design guidelines for amphibian tunnels and guiding fences stand on a weak foundation. 

In this subproject we derived valuable results regarding effectiveness of amphibian mitigation measures in reducing roadkill and barrier effects. 

Management and construction of road infrastructure habitats for biodiversity

Considerable efforts are put into monitoring and management of species-rich road verges. However, monitoring results point at declining species richness in many areas, in spite of presumably adapted management.

In this subproject we use field data to analyse which environmental conditions, including management, that constitute ecological key factors for different biodiversity values in road infrastructure habitats.

Management and construction of rail infrastructure habitats for biodiversity

Recently, it has been shown that many parts of the railway system are surprisingly species-rich and constitute important refugias for threatened insect species and rare types of plant communities. 

In this subproject we use field data to analyse which environmental conditions, including management, that constitute ecological key factors for different biodiversity values in railway infrastructure habitats.

Ecological functions of infrastructure habitats

An overview of the different functions of infrastructure habitats is important for setting up of conservation goals and thereby for designing management activities that give the best possible biodiversity effects.

In this subproject we use information from the subprojects on road and rail infrastructure habitats to qualitatively identify different ecological functions.