Roads are a major problem for the planet. Globally, many new roads are built into rainforest to support logging or dam building. These roads start a process of exploitation that is hard to stop and that transforms habitats and provides access to poachers. Since 2000, for instance, 30,000 miles of new roads have been cut into African rainforests. It's no surprise that poachers have killed two thirds of the forest elephants in that same period.
The rainforests will not survive the combined pressures of logging, settlement and clearance for pasture and cropping that road-building makes possible. And many species will not survive the loss of their rainforest homes.
This has happened at extraordinary speed and there's no sign that it's slowing down. The G20 meeting last October argued for annual spending of $2T pa (that's $2 million million pa) on infrastructure in developing countries. Only a fraction of that is likely to be roads; but that's still a lot of roads (and railways, power stations, airports, etc.)
Most of the species that existed 100 years ago are still with us, though in much reduced numbers. Their habitats have been greatly reduced and many will be gone in much less than 100 years if development continues. For some threatened species a few dozen animals may survive in zoos and game reserves. Many will disappeared leaving no more than stuffed examples in museums, films, if we're lucky, DNA sequences in some database.
A tragic loss and little time left.