Considerations on the geometric design of low-volume roads

Abstract

Technical, economic and social criteria have to be considered for justifying the adequacy of the new low volume roads, in Romania. The high investment costs in this field are the consequence of the non satisfactory viability state, which characterizes the majority of the local road network of Romania, where graveled roads represent more than 25,000 km, and earthy roads represent more than 8,500 km. Only 10% of the local roads are modernized, 30% are provided with semi-permanent pavements, and most of them have an exceeded service life. In accordance to a "strategic policy" design of the infrastructure of a local road is justified for a minimum of 15 years service life, while the "tactic policy" may be adopted when designing the road structure. The paper presents the design principles of low volume roads, taking into account the local conditions. There are emphasized the following: the local road functions - both public and social ones, the required conditions for the geometric design, the importance of multi-criteria methods as economical tools .The design principles according to the Romanian technical provisions for horizontal and vertical alignment, and that of the cross sections are also discussed. The concept of the ecological resistance is also presented .The conclusions emphasize that both design and construction of a low volume road has to be framed into the concept of durable development.