Crossing to Sustainability: A Role for Design in Overcoming Road Effects

The Earth's network of roads is vast and is reaching new regions with each year that passes. The effects of roads as barriers to animal movement and as conduits for other threats to the conservation of natural systems are well documented. Wildlife crossings can successfully mitigate some of the negative effects of roads by making it possible for wildlife to traverse even major highways safely. However, despite decades of successful deployment, the use of crossings remains uncommon. Their continuing rarity has a variety of origins, but cost and public appreciation of their benefits remain the most important limiting factors. We hypothesize that design can address both challenges. Here we describe a crossing design that is unconventional by current standards. We employ massed wood in a bridge crossing using laminated modules. These modules make it straightforward to customize the structure to its site while also keeping costs low, both because the materials are relatively inexpensive and because the need for specialized labor has been minimized. Other benefits include the rapidity with which the structure can be raised and the reduced need to close roadways during construction. Collectively, these innovations are intended to make crossings much less expensive and more easily adapted to a particular application. The use of massed wood creates a structure that is strong enough to support landscaping on its surface, is both weather- and fire-resistant, and that sequesters many tons of carbon in a long lasting structure.