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Road safety is still a big problem in Ethiopia, especially in mountainous and inter-regional corridors where bad geometry, difficult terrain, and mixed traffic make  for dangerous areas. This study offers a thorough geometric design assessment and  comparative analysis of the Dilla–Bulle–Haro Wachu Road, a 68.2 km connector  road that crosses the escarpment and mountainous terrain of southern Ethiopia. The study assesses the current horizontal and vertical alignment in relation to two specific geometric design standards: the Ethiopian Roads Authority (ERA) Geometric Design Manual (2013) Design Class DC6, and the Russian SP 34.13330."Automobile Roads" in 2021, Category III. The study used AutoCAD Civil 3D to model the terrain and analyze the slopes. It looked at horizontal curves and vertical points across four types of terrain: Town, Rolling, Mountainous, and Escarpment. The most important findings show that both standards have a lot of non-compliance with minimum horizontal curve radius requirements. ERA DC6 says that 40.9% of escarpment curves and 29.5% of mountainous curves do not meet the minimum radius requirements. 27.5% of curves in difficult terrain dont meet Russian Category III standards because their radii are less than the 100 m minimum needed for a design speed of 50 km/h. Vertical alignment analysis found slopes as steep as 12%, which is higher than the limits set by ERA DC6 (9% maximum) and Russia (8% maximum). The compliance rates for these two standards were 85.3% and 72.1%, respectively. The comparative analysis shows that the design philosophies are very different. ERA DC6 focuses on higher operational speeds (70 km/h in mountainous terrain) and building costs, while Russian standards focus on terrain adaptability through lower design speeds (50 km/h), smaller minimum radii (100 m), and stricter gradient controls. Even with the highest super-elevation (8%), many curves with radii less than 73 m are still not safe at 50 km/h. The study finds that the best way to design Ethiopian mountainous corridors is to use a hybrid approach: use ERA DC6 standards for flat and rolling terrain and Russian Category III standards lower design speeds, smaller minimum radii, and stricter gradient limits for escarpment and mountainous sections. This method that adapts to the terrain makes things safer, makes it easier for heavy vehicles to work, cuts down on unnecessary earthwork, and has less of an effect on the environment. Suggestions include making the design speed more reasonable, optimizing the super-elevation, improving the geometry at important curves (especially at stations 9+616.161, 12+408.584, and 28+702.057), putting in safety measures (warning signs, high-friction surface treatment, guardrails), and writing down formal design exceptions when reconstruction isnt possible. The results create a framework that can be used to redesign the geometry of similar high-risk corridors in other parts of Ethiopias highlands and escarpment zones.

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