The study focused on two different locations. Paw prints were registered and counted to ascertain how many wild animals used the ecoducts. And infrared counters – that did not distinguish between cyclists and pedestrians – were used to count visitors.
One ecoduct contains a semi-metalled bike path used by some 180,000 pedestrians and cyclists annually. The other ecoduct has been provided with surfacing and accommodates some 60,000 visitors annually.
Both ecoducts perform no less well than ecoducts without recreational joint use, as far as the number of passing wildlife is concerned, Alterra ascertained, even on days with large numbers of visitors. Some species, like roe deer or badger, cross the ecoducts studied even more often. They do cross somewhat faster than on other ecoducts, but that appears to be related to the width of the ecoduct as well.
An ecoduct should be preferably 40 to 60 metres wide, plus the width of the recreational zone, Alterra recommends. In addition paths for human visitors should be constructed and combined if expansion is required. The paths should also be separated by a man-resistant but fauna-permissive fence between the path and the nature zone, a visual screen is also required. Crossing wildlife should also have ample room for shelter on the ecoduct.