Short answers, pulled from the story.
The Organization for Economic Co-operation and Development defines a road as a line of communication using a stabilized base other than rails or air strips open to public traffic. This definition includes bridges, tunnels, supporting structures, junctions, crossings, interchanges, and toll roads but excludes cycle paths.
The world's oldest known paved road was constructed in Egypt some time between 2600 BC and 2200 BC. Corduroy roads dating back to 4000 BC exist in Glastonbury, England while the Sweet Track timber trackway in Northern Europe was built in winter 3807 BC or spring 3806 BC according to tree-ring dating.
Experiments called the AASHO Road Test carried out in the late 1950s show that effective damage done to the road is roughly proportional to the fourth power of axle weight. A typical tractor-trailer weighing 80,000 pounds does 7,800 times more damage than a passenger vehicle.
The United States has the largest network of roads of any country as of 2009. The Republic of India holds second-largest system globally with data from 2013 while China ranks third with figures from 2007.
Road runoff is a major source of nickel copper zinc cadmium lead and polycyclic aromatic hydrocarbons created as combustion byproducts. De-icing chemicals and sand can run off into roadsides contaminating groundwater and polluting surface waters while motor vehicle emissions contribute air pollution with concentrations greater near roads than at distance away.