2024-09-17-世界银行-非洲公路网的最佳投资（英）_88页_18mb

Optimal Investments in Africa's Road Network

Methodology & Findings Overview

This paper characterizes economically optimal investments in Africa's road network using spatial equilibrium modeling and cost-benefit analysis. Key findings include:

• Current efficiency: Route efficiency averages 0.68, lower than the US (0.84), due to poor roads and cross-border frictions.
• Border frictions: Median African border crossing costs equate to ~1,043km road distance and 3.2 days travel time, reducing market access by 26-78%.
• Investment priorities: New trans-Saharan roads, Morocco-Algeria reopening, and corridors connecting major cities (e.g., Lagos-Cairo, Kinshasa-Nairobi) yield highest returns.
• Cost-benefit: New links cost >600K USD/km, full upgrades ~1.5-6M USD/km. Proposals yield 1-5% market access gains without frictions; 1-2% with frictions. Packages costing $60B-$17B offer >1 and 4 $/min/$ returns without frictions.
• General equilibrium: Welfare gains range 0.04-7.5%, higher under increasing returns to infrastructure or inequality aversion. Low trade elasticity (σ~3.8) reduces incentives for central African investments.

Policy Recommendations

• Prioritize local upgrades and national corridors (Nigeria, Egypt, South Africa).
• Reduce border frictions (equivalent to 80-90% of total delay).
• For trans-African projects, focus on low σ countries and strategic links (e.g., Morocco-Algeria, Congo-related corridors).