Impact of Horizontal Curves and Gradient on the Speed of Heavy Vehicles on Two-Lane Rural Mountain Roads: Case of the LojaCatamayo Road

Abstract

This study analyzes the speed behavior of heavy vehicles on rural mountain roads, specifically on the Loja-Catamayo road in Ecuador. This analysis is crucial for improving road safety as the operating speed of these vehicles is influenced by multiple factors, including road geometric design, topography, and weather conditions. The study focuses on evaluating the impact of curve radii and gradients on the speed of heavy vehicles. Data collection was performed using a high-precision GPS device installed in a follow-up vehicle that accompanied 14 trucks during their journeys on the road. The obtained data were analyzed using statistical methods, including normality tests and one-way ANOVA, considering two main variables: curve radii and gradients. The results show that both curve radii and gradients have a significant impact on the speed of heavy vehicles. Curves with radii less than 50 meters and steep gradients tend to reduce vehicle speed, indicating greater caution by drivers on these road segments. Additionally, it was found that vehicle speeds are higher on the outbound route (Loja-Catamayo) due to the terrain characteristics. The study's conclusions highlight the importance of considering these geometric variables in the design and maintenance of rural roads in mountainous environments to improve road safety. The findings provide valuable information for planning and implementing speed control measures and optimizing road design.