Switzerland has one of the densest infrastructure networks of Europe (3-4 km/km2 on the Central Plateau). Fragmentation of natural habitats has become a major conservation concern as vulnerable species become rarer and the red list of endangered species becomes longer. The mortality of animals on roads remains high, with more than 8,000 roe deer killed yearly by traffic. Many amphibian spawn sites along lakeshore have been cut off from their wintering grounds by roads, with populations then disappearing. Highways have proven to be an impassable barrier for the lynx, impeding colonization of eastern Switzerland. Switzerland participated actively in the COST 341 European research program “Habitat fragmentation due to transportation infrastructure.” A census of bottlenecks where infrastructure intercepts important wildlife corridors was carried out during this program. Fifty-one points needing restoration measures were identified. Many of these are along firstgeneration highways built along an east-west axis and cutting off any possible exchange between wildlife populations in the Alps and the Jura. A ministerial guideline sealed a partnership between the Swiss Agency for Environment, Forests, and Landscape (SAEFL) and the Swiss Federal Roads Authority. The defragmentation program has been included in the highway-maintenance program and is to take place over the next 20 years. Five conflict points have been recently retrofitted in the context of highway-widening schemes. A program methodology is being developed. Conflict points will be addressed as the involved highway section comes up for maintenance. In order to facilitate long-term planning, different instruments have been developed. Standards have been defined by the Swiss Association of Road and Transportation Experts (VSS 2004) to guide engineers and biologists in the analysis of existing structures and potential permeability for fauna. Criteria were developed to facilitate the choice of the optimal type of passage for each given situation. Further research and standards are being launched to homogenize monitoring programs and develop best practice for retrofitting culverts, as well as to anticipate and eliminate wildlife traps created by certain structures.

The barrier effect of roads is now well documented and solutions such as fauna passages are readily imple¬mented (Trocmé et al. 2002). Less well known is the mortality caused by specific engineering structures used along roads, such as drainage systems. This research focuses on censusing wildlife hazards caused by such structures and developing solutions. Structures such as drainage systems, kerbs, gullies, culverts, noise barriers, lighting, retaining walls, were all examined. Small fauna specialists and maintenance teams were interviewed to gather information on known impacts as well as solutions found. Wildlife hazards were identified. Drainage systems with gullies often provoke high mortality for amphibians and other small fauna. Other structures such as retaining walls increase fragmentation by creating complete barriers. Designs more permeable to wildlife need to be enhanced. Certain solutions such as escape ramps from drainage systems have been tested on a local scale.

After identifying the problematic structures an analysis of Swiss road standards was made underlining which ones needed to be completed or modified so as to limit the impact of transport structures on wildlife. Further studies will be necessary so as to develop standardised solutions taking into account wildlife, maintenance and safety issues.