Building a new highway destroys habitats and can lead to soil erosion

Because by building a road, your removing land that was once occupied by nature and dividing the animals habitats. With trees being removed, it exposes soil to the climate more, reduces the woods capacity to absorb floods leaving the top layer being carried off, and dried in hotter climates.  

Builsinf new highways will mean more nauteal land will be used up, this land will have been used previously by animals who will have made a home there.. AKA. a habitat ... To live there, when new highways are built habitats are destroyed and can lead to soil erosion from less nutrients entering the soil due to it being covered by gravel from the highway