ABSTRACT
Engineers are challenged to design highways that meet the needs of different travelers under various conditions and constraints. Travelers encompass pedestrians, scooter and moped riders, cyclists, and motorized vehicle drivers. Performance metrics include travel time and distance, travel reliability, and travel safety. Constraints involve budget, environmental regulations, and public consensus. Traveled way is a lane where vehicles travel. A travel lane is a delineated path traveled by a single profile of vehicles. Traveled way includes lanes for both motorized and nonmotorized travel. The traveled way is most likely paved with either bituminous or Portland cement concrete. A roadway median is a strip of land situated between two traveled ways in the opposite direction. Median separates opposing vehicles – stopping errant vehicles from crossing-over and thus preventing head-on collisions. A shoulder is a specially prepared surface area abutting from the edge of the traveled lane.
