Two-lane highways are the most predominant systems world wide. They make up approximately 85% of Latin America's main road network which carries 76% of its traffic. A large proportion of its traffic volume (about 80%) consists of heavy vehicles and 45% of it is built on mountain or rough terrain. Parameters, such as the percentage passing delay time or average travel speed, set out in widely - used TRB-1994 Highway Capacity Manual do not correspond to conditions in Latin American countries and do not take into account other elements such as "passing" and "distance" which affect the capacity of this type of highway. In addition, the HCM's directional distribution factors for traffic need rethinking because they were determined analytically with little detail. The paper will explain the differences between the HCM and actual conditions,it will also establish the effect on passing manoeuvres and two-lane highway (A)
Abstract