A guide to help road builders protect the habitat of the UK's dwindling population of butterflies has been published.
The marsh fritillary butterfly is one species to benefit from the scheme
The Butterfly Handbook encourages engineers to include features and plants that will encourage wildlife.
Conservationists hope better designed roads will provide breeding sites for the creatures, as well as acting as links between suitable habitat.
The handbook has been co-published by English Nature and the Highways Agency.
English Nature's chief scientist Dr Keith Duff said the guide showed that new roads were not necessarily bad news for local wildlife.
"It actually depends where you put them, and how you design and build them," he said.
"We all know that roads often destroy habitat, break it up into bits and cause pollution, but if designed properly you can create habitat corridors that are really good for wildlife."
The publication offers guidance on habitat sizes, species' locations, breeding areas and colonisation patterns.
Conservationists say butterflies have probably never been as endangered as they are today following decades of loss of key habitats.
Of the 56 species of butterflies found in the UK, 26 are recognised as species that need their habitat protected in order to ensure their long term survival.
In the handbook's foreword, Dr Martin Warren, chief executive of Butterfly Conservation charity, said: "This report is extremely valuable and timely as it concerns an increasingly important habitat for butterflies and other insects.
"Road verges can help conserve butterflies and other wildlife as they are an opportunity to provide suitable breeding habitats for many species, and provide crucial links between the patches of habitat that remain," Dr Warren added.
In the past, wildlife campaigners and construction firms have been involved in lengthy battles about the building of new roads.
One of the most famous clashes was back in 1996, over the proposed route for the Newbury bypass.
The handbook lists a number of recent projects that included butterfly-friendly measures, including an extension of the M40 in Oxfordshire that was rerouted to protect the local habitat of black hairstreak butterflies.
English Nature's Dr Duff hopes the guide will help engineers and environmentalists form a closer working relationship.
"These days, conservationists seek to engage with road builders at the start in order to build an understanding," he said.
"You can then make sure that things are designed to work for people and work for wildlife."