John the Baptist described three basic principles of highway building, making things straight, level and smooth. Paved streets dating back before Abraham have been found in Ur. The Roman Empire built major roads covering almost 80,000 kilometers (50,000 miles). To create a modern highway, surveyors must calculate the best route, it must be designed and approved, land must be purchased, rock and earth must be removed by blasting and digging, depressions must be filled, and embankments, bridges and tunnels must be built following prescribed maximum gradients. Drainage and water courses must be integrated. All this is before the first level of road bed is put down. That may consist of aggregate base, base, intermediate and surface layers. The thickness of these layers varies around the world. John’s use of a road building metaphor pictures preparation to receive Christ.