Comparison of Rightofway in Mountainous and Valley Forest Roads

The aesthetic quality of hyrcanian forest roadsides is influenced by a number of factors. Among these factors are rightofway width, earth working (cut and fill slopes), adjacent land use, topography and existing vegetation. The main objectives of this study were to comparison of rightofway in mountainous and valley forest roads. For this purpose, were measured real right of way and earth working limit using laser rangefinder and mapping index for each road. Results showed, there was significant difference between the earth working limit and real right of way in valley and mountainous forest roads (P< 0.05). Also, was found significant linear relationship, with equation of Y = 0.249X + 2.202 (R² = 0.69) between range slope and real right of way in mountainous forest road. The rate of earth working limit and real right of way increased with increasing range slope. Horizontal curve radius has an important effect on geometric design of road. So that, the rate of earth work limit decreased with increasing horizontal curve radius. Also, there was a significant linear relationship between horizontal curve radius and real right of way in mountainous (R² = 0.65) and valley (R² = 0.49) forest roads. According to results, right of way and earth working limit should be carefully selected, not only to minimize the total road cost but also to reduce the environmental impact and to improve driver safety.