Misallocation of resources by the government and unfortunately political agendas. In Canada, roads are a provincial responsibility, and unfortunately the Nova Scotia government isn't the most competent cats around when it comes to accounting.
Governments fund roads that don't need funding and neglect roads that need the funding. Unfortunately, sometimes the motivations are political in nature. If a certain district voted heavily for the winning party, you can bet all the roads of that district are well paved, while a district who voted heavily for a rival are driving in dirt.