Roadsides as refuges for threatened species

In many occasions, road side vegetation has shown to provide valuable if not essential habitat to rare and endagared plant and animal species. The potential of roadsides to provide habitat in otherwise heavily affected landscapes has been discussed worldwide, but still road managers and maintenance entrepreneurs have not yet understood the fully grasped these opportunities. On the other hand, there is the risk to create ecological traps that, although they seemingly support lots of wildlife, may actually drain the landscape. How can benefits and risks be balanced?