Analysis of widening interventions of two-lane rural highways

Abstract

When operational problems occur on two-lane rural highways, many managers consider duplication as the main option. However, configurations such as passing lanes and “2+1” roads are intermediate solutions widely used in other countries to improve operational conditions. Thus, the main objective of this dissertation was to analyze the operational conditions and the feasibility of widening interventions of two-lane rural highways, such as i) passing lanes; ii) 2+1 road; iii) duplication. The proposed method had three main steps: i) data collection and treatment; ii) operational analysis by determining the levels of service using the 6th and 7th editions of the HCM. The results obtained with HCM-7 indicated that the passing lanes could promote one level of service improvement, which can last for seven to ten years. Similarly, 2+1 highways can improve operational conditions for 16 years, and highway duplication is not necessary during this period. Segments with level terrain presented results (obtained with HCM-6) that take an average of six years to be equivalent to the results obtained for segments with rolling terrain, which represents an operational advantage. The level of service obtained with HCM-7 was considerably better than applying HCM-6. The difference to achieve the level of service “D” for rolling terrain, between both manuals, was 20 years.